UNIVERSITY  OF  IllWOtS 

JUL  1 4 1915 

SPECULATIONS. 


SOLAR  HEAT,  GRAVITATION, 

AND 

SUN  SPOTS. 


By  J.  H.  KEDZIE,  Ph.  D. 


Whence  are  thy  beams,  O,  Sun!  thy  everlasting  light?— Ossian. 

Some  are  much  surprised  that  I should,  as  they  think,  venture  to  oppose 
the  conclusions  of  Newton;  but  here  there  is  a mistake.  I do  not  oppose 
Newton  on  any  point;  it  is  rather  those  who  sustain  the  idea  of  action  at  a 
distance  that  contradict  him.— Dr.  Faraday. 

The  very  source  and  font  of  day 
Is  dashed  with  wandering  isles  of  night.— Belgravia. 


SECOND  EDITION. 


CHICAGO: 

S.  C.  GRIGGS  AND  COMPANY. 

1891. 


Copyright,  1886, 

By  S.  C.  GRIGGS  AND  COMPANY. 


KNIGHT  £ LEONARD. 


s 2/5.  T 


o 

o 


«f? 


To  the  Members  and  Fellows  of  the  A.  A.  A.  S. : 

The  maximum  sun  spot  period  is  again  approaching, 
and  so  is  the  perihelion  of  Jupiter.  These  two  grand 
celestial  phenomena  have  probably  run  their  cycles  in 
equal  times  since  the  birth  of  our  system,  and  will  un- 
doubtedly continue  to  do  so  while  our  system  endures. 

The  period  of  Jupiter's  perihelia  is  exactly  11T8¥6F  years, 
that  of  the  sun  spot  maximum  is  approximately  the  same, 
though,  from  its  nature,  it  cannot  be  sharply  defined. 
From  this  fact  and  all  the  other  facts  in  relation  to  these 
wonderful  phenomena,  which  I need  not  here  rehearse,  I 
cannot  avoid  the  conviction  that  there  is  a physical  con- 
nection between  the  perihelia  of  Jupiter  and  the  periods 
of  maximum  solar  maculation,  though  modified  by  the 
action  of  all  the  other  planets  and  satellites.  The  strong 
interest  excited  by  the  reappearance  of  large  spots  on  the 
sun  makes  the  present  an  appropriate  occasion  for  again 
calling  the  attention  of  scientists  to  the  subject,  and  is 
my  excuse  for  presenting  to  the  members  and  fellows  of 
this  Society  Part  III  of  my  work  on  Solar  Heat,  Gravita- 
tion and  Sun  Spots. 

The  only  favor  I ask  in  return  from  those  who  have  the 
facilities  and  leisure  for  observations,  especially  by  photo- 
graphy, as  well  as  from  all  others  who  may  do  me  the 
honor  to  read  the  pamphlet,  is  that  they  will  immediately 
communicate  to  me  briefly  their  impressions,  whether 
from  the  book  or  from  their  own  observations. 


Very  truly  yours, 


August  1,  1891. 


J.  H.  Kedzie, 

Evanston,  111. 


PREFACE. 


HE  author’s  task  is  done,  and  it  only  remains  for 


him  to  apologize  to  the  public  for  inflicting  one 
more  book  on  a book-ridden  world. 

The  public,  however,  cannot  complain  of  a surfeit 
of  literature  on  the  subject  I have  chosen.  Probably 
not  one  work  has  been  written  on  the  Sun  — to  us  the 
grandest  and  most  beneficent  object  in  nature  — to  one 
million  of  fiction. 

As  will  be ' seen  from  the  title,  the  themes  here 
treated  are  three  apparently  disconnected  subjects,  but 
if  I am  correct,  they  form  a closely  connected  trinity, 
depending  upon  a common  principle. 

The  positions  advanced  in  this  work  may  seem  bold 
and,  at  first  glance,  revolutionary.  But  a closer  view, 
I trust,  will  convince  the  reader  that  not  a single  well 
settled  principle  of  science  has  been  assailed.  Thus : 
On  the  subject  of  solar  heat  there  are  not  less  than  five 
or  six  different  theories  advanced  by  eminent  scientists. 
A new  theory  cannot,  therefore,  be  considered  as  con- 
flicting with  any  settled  doctrine  on  this  subject. 

In  regard  to  gravitation,  the  field  is  still  more  com- 
pletely unpreoccupied.  There  is  no  settled  doctrine  as 
to  the  cause  of  gravitation,  and  not  even  a plausible 


IV 


PREFACE. 


theory  that  I am  aware  of.  It  is  equally  true  that  there 
is  no  settled  doctrine  among  scientists  in  regard  to  the 
cause  of  sun  spots.  A number  of  ingenious  theories 
have  been  advanced,  but  none  have  met  with  general 
acceptance,  and  there  is  not  one  which  even  professes 
to  account  for  all  the  phases  of  those  wonderful  phe- 
nomena. 

The  writer  thought  at  one  time  that  he  would  be 
obliged  to  dissent  from  a generally  accepted  doctrine  in 
regard  to  “ potential  energy  ” ; but  subsequent  reading 
showed  him  that  he  had  been  anticipated,  in  the  views 
advanced  by  at  least  two  scholars  of  eminence  — Judge 
J.  B.  Stallo  and  S.  To!  ver  Preston. 

The  writer,  therefore,  though  a debtor  to  all  scholars, 
from  the  times  of  Copernicus  to  the  present,  has  im- 
pugned the  accepted  work  of  none.  On  the  contrary, 
he  has  addressed  himself  wholly  to  unsolved  problems 
in  science.  Since  astronomers  have  swept  the  vault  of 
heaven  with  their  magic  tubes,  and  calculated  the  paths 
of  planets  and  satellites  by  the  laws  of  projection  and 
gravitation,  it  cannot  be  considered  presumptuous  to 
inquire  reverently  into  the  source  of  gravitation  itself; 
and  if  in  so  doing  the  suspicion  arises,  and  will  not 
down,  that  gravitation  is  connected  on  one  hand  with 
solar  heat,  and  on  the  other  with  sun  spots,  by  a single 
well  known  principle,  what  is  the  wrriter  to  do  but  to 
announce  his  suspicion,  and  give  his  reasons  therefor  ? 

Though  the  writer  has  chosen  to  apply  the  term 


PREFACE. 


V 


“ speculations  ” to  tlie  views  herein  advanced  until  in- 
dorsed by  higher  authority,  still  he  must  confess  that 
not  without  some  misgivings  he  has  finally  become  a 
convert  to  his  own  opinions.  He  has,  therefore,  no 
apology  to  offer  for  advocating  what  he  believes  to  be 
true  with  all  the  earnestness  and  zeal  which  truth  de- 
mands of  her  votaries. 

For  all  the  facts  and  principles  of  value  in  the  fol- 
lowing pages,  though  not  always  for  the  use  made  of 
them,  the  writer  is  indebted,  as  all  the  world  is,  first  to 
Sir  Isaac  Newton;  and  scarcely  less  to  the  great  minds 
of  the  present  day.  Though  illustrious  all,  they  are  too 
numerous  to  be  mentioned  by  name.  I desire  to  ac- 
knowledge my  indebtedness  to  all  as  fully  as  if  I could 
thank  each  one  in  person. 

These  chapters  are  most  deferentially  submitted  by 
the  author  to  the  candid  judgment  of  the  learned  public. 
He  cannot  expect,  and  would  not  desire,  the  acceptance 
of  the  views  here  presented  until  it  is  found  on  the  full- 
est examination,  that  they  conform  to  all  the  conditions 
of  truth,  and  conflict  with  no  settled  fact  or  principle  of 
science. 

J.  H.  KEDZIE. 

Evanston,  III.,  May,  1886. 


Digitized  by  the  Internet  Archive 
in  2017  with  funding  from 

University  of  Illinois  Urbana-Champaign  Alternates 


https://archive.org/details/speculationssolaOOkedz 


PART  III.- SUN  SPOTS. 


CHAPTER  I. 


GENERAL  DESCRIPTION  AND  HISTORY. 


The  very  source  and  font  of  day 
Is  dashed  with  wandering  isles  of  night. 


— Belgravia. 


OR  nearly  three  hundred  years  the  scientific  world 


JL  has  been  familiar  with  spots  on  the  sun,  discovered 
almost  simultaneously  by  Galileo,  Fabricius,  and  Schei- 
ner.  An  amusing  incident  is  related  of  the  latter,  who 
was  a Jesuit  brother.  On  informing  his  superior  of 
his  discovery,  and  asking  to  be  allowed  to  publish  the 
same,  the  superior  replied  : “ Go,  my  son ; tranquillize 
yourself,  and  rest  assured  that  what  you  take  for  spots 
in  the  sun  are  the  faults  of  your  glasses  or  of  your 
eyes.  I have  read  Aristotle's  writings  from  end  to  end 
many  times,  and  I can  assure  you  that  I have  nowhere 
found  in  them  anything  similar  to  what  you  mention.” 

To  be  more  specific  : The  Jionored  name  of  Galileo 
is  credited  with  the  first  discovery  by  telescope  of  sun 
spots,  in  October,  1610.  Fabricius  followed  closely 
after,  in  December  of  the  same  year,  and  only  a few 
months  later,  in  March,  1611,  Scheiner  made  the  same 
discovery.  All  were  original  discoveries,  as  each  worked 
in  entire  ignorance  of  the  labors  of  the  others.  As 
Fabricius  was  the  first  to  publish  his  discovery,  in  June, 


219 


220 


SUN  SPOTS. 


1611,  the  discovery  is  credited  to  him,  though  the 
others  are  entitled  to  equal  honors. 

As  large  sun  spots  are  visible  to  the  naked  eye,  many 
were  no  doubt  seen  before  the  invention  of  the  tele- 
scope. The  records  of  that  curious  people,  the  Chinese, 
curious  in  two  senses,  afford  evidence  of  such  observa- 
tions. Dark  spots  had  also  been  observed  by  Kepler 
and  other  European  scholars  before  the  invention  of 
the  telescope ; but  as  they  could  not  be  examined  in 
detail,  they  attracted  but  little  attention. 

These  spots  are  often  of  enormous  extent,  covering 
sometimes  millions  and  even  billions  of  square  miles. 
They  generally  open  as  small  points,  enlarge  rapidly 
till  they  attain  their  maximum,  and  after  a period  of 
comparative  stability,  varying  from  a few  days  to  sev- 
eral months,  fill  up  and  disappear. 

They  are  mostly  confined  to  that  part  of  the  sun’s 
surface  corresponding  to  our  torrid  zone,  or  rather  to 
two  zones,  one  on  each  side  of  the  equator,  bounded  by 
parallels  about  thirty  degrees  north  and  south  of  the 
equator.  These  zones  of  maximum  sun  spots  shade 
out  each  way,  so  that  very  few  are  found  within  ten 
degrees  of  the  equator,,  or  beyond  thirty  degrees  north 
and  south  of  the  same. 

These  spots  are  dark  at  the  bottom  and  partially 
lighted  on  the  penumbral  edges,  which  extend  to  the 
depths  of  thousands  of  miles. 

They  increase  and  diminish  in  numbers  at  nearly 
regular  periods  of  about  eleven  years.  The  upland  or 
plain  in  which  these  crater-like  openings  appear  is  of 
the  substance  denominated  the  sun’s  photosphere ; that 
is,  the  incandescent  surface  which  sends  forth  the  light 
and  heat  of  the  sun.  This,  as  I venture  to  conjecture, 


GENERAL  DESCRIPTION  AND  HISTORY. 


221 


is  composed  of  the  sublimated  vapors  of  carbon  float- 
ing in  an  atmosphere  of  metallic  gases.  Immediately 
below  the  surface  of  the  photosphere  is  the  stratum  of 
penumbral  clouds,  no  doubt  composed  of  the  same  ma- 
terials, but  at  a lower  temperature.  Still  lower  is  the 
nucleus  or  body  of  the  sun,  sometimes  called  the 
umbra.  The  nucleus  is  generally  believed  to  be  liquid 
in  form,  but  by  some  to  be  composed  of  viscid  gases. 
The  spectroscope  seems  to  pronounce  in  favor  of  a 
liquid,  composed  of  the  most  refractory  elementary 
substances,  reduced  to  that  form  by  intense  heat. 
These  spots  often  pass  entirely  across  the  sun’s  disc 
by  virtue  of  his  revolution,  and  have  sometimes  been 
mistaken  for  the  transits  of  inferior  planets.  The  sur- 
face of  the  nucleus  is  overlaid  by  transparent  absorbing 
gases,  by  the  action  of  which  the  Frauenhofer  lines 
of  the  spectrum  are  produced. 

The  appearance  of  these  spots  in  perspective  at  the 
edges  of  the  sun’s  disc  clearly  shows  that  they  are  im- 
mense chasms  in  the  strata  of  the  photospheric  and 
penumbral  clouds,  laying  bare  for  the  time  the  inner, 
darker  and  cooler  nucleus  of  the  sun. 

They  are  exceedingly  variable  in  size  and  duration. 
One  has  been  seen  almost  two  hundred  thousand  miles 
in  diameter,  and  covering  an  area  of  twenty-five  billions 
of  square  miles.  Their  duration  also  varies  from  a few 
hours  to  whole  days,  weeks,  and  months.  They  form  a 
puzzle  to  philosophers.  While  the  facts  are  obscure,  not 
for  the  want,  but  rather  the  excess,  of  light,  and  also  the 
immense  distance  of  the  sun,  these  philosophers  have 
not  hesitated  to  draw  largely  upon  their  imaginations 
for  hypothetical  explanations.  There  is  no  harm  in 
this,  so  long  as  they  are  given  merely  as  hypotheses, 


222 


SUN  SPOTS. 


and  kept  strictly  within  the  limits  of  known  facts.  A 
hypothesis,  to  be  of  any  value,  must  conform  strictly  to 
the  known  telescopic  and  spectroscopic  conditions  under 
which  these  spots  have  been  observed. 

It  is  entirely  unnecessary,  even  if  I possessed  the 
time  and  qualifications  for  the  task,  to  examine  critically 
all  the  theories  advanced  in  explanation  of  these  phe- 
nomena. A number  of  them  are  peremptorily  excluded 
by  telescopic  and  spectroscopic  observations.  Of  those 
remaining,  no  one  is  satisfactory  to  all  students  of  solar 
physics.  Anticipating  possibly  a similar  fate  for  my 
own  theory,  I proceed  to  unfold  it  for  what  it  is  worth. 


Fig.  12.— Spot  of  July  1G,  18G6. 

We  here  call  attention  to  a very  symmetrical  illus- 
tration of  a sun  spot,  from  uThe  Sun,”  by  Prof.  Young. 
We  quote  from  page  115,  on  which  this  figure  occurs, 
as  follows: 

“A  well  formed  solar  spot  consists,  generally  speaking,  of  two 
portions  — a very  dark,  irregular,  central  portion,  called  the  umbra, 


GENERAL  DESCRIPTION  AND  HISTORY. 


223 


surrounded  by  a shade  or  fringe  called  the  penumbra,  less  dark,  and 
for  the  most  part  made  up  of  filaments  directed  radially  inward. 
The  appearance  of  things,  under  ordinary  circumstances  of  seeing, 
is  as  if  the  umbra  were  a hole,  and  the  penumbral  filaments  overhung 
and  partly  shaded  it  from  our  view,  like  bushes  at  the  mouth  of  a 
cavern.  I say  as  if,  and  very  possibly  this  is  the  actual  case,  the 
central  portion  being  a real  cavity  filled  with  less  luminous  matter, 
and  depressed  below  the  general  level  of  the  photosphere,  while  the 
penumbra  overhangs  the  edge.” 

To  my  eye  the  penumbra  resembles  more  nearly  the 
shelving  banks  of  a deep  excavation.  This  figure  also 
represents  beautifully  the  bright  points  called  “ gran- 
ules,” and  the  dark  reticulation  called  “ pores’5  in  the 
general  surface  of  the  photosphere.  It  also  exhibits  to 
advantage  the  bright  fringe,  often  club-shaped,  at  the 
inner  edge  of  the  penumbra  hereafter  mentioned. 


CHAPTER  II. 


A NEW  THEORY  OF  SUN  SPOTS  — THE  PHOTOSPHERE 
THE  HOTTEST  PART  OF  THE  SUN. 


And  now  the  sun  — 


Insufferably  brilliant,  and  his  blaze 

Tinges  with  flowing  gold  the  icy  head  - 

Of  peaks  which  rise  above  the  clouds,  and  gaze 

On  budding  landscape,  hills,  woods,  meadows,  lakes, 

Rivers,  and  winding  rivulets,  where  plays 

The  wave  in  lines  of  silver.  — Percival. 

IIEN  we  find  a rule  to  which  there  is  no  excep- 


V V tion,  it  rises  to  the  dignity  of  a law ; and  one 
law  thoroughly  understood  and  applied  will  often  throw 
a flood  of  light  on  many  problems.  The  law  to  which 
I wish  to  direct  attention  is,  that  the  more  highly  an 
elementary  body  is  heated,  the  more  brilliantly  white  it 
becomes.  Applied  to  the  sun,  we  find  the  facute,  which 
are  the  crests  of  the  photosphere,  or  the  sun’s  Hima- 
layan mountains  of  light,  are  the  most  dazzlingly  white. 
The  general  surface  of  the  photosphere  is  of  a milder 
intensity,  and  the  brightness  continues  to  decrease 
through  the  penumbral  strata  to  the  nucleus,  which 
appears  to  be  entirely  black,  of  course  by  contrast. 
The  conclusion  seems  inevitable,  that  the  outer  envelope 
of  the  sun,  next  to  its  purely  gaseous  atmosphere,  is  by 
far  the  hottest  portion.  I regard  the  photosphere,  with 
its  umbral  and  penumbral  strata  lying  in  immediate 
contact  with  the  nucleus,  as  a part  of  the  sun  rather 


224 


A NEW  THEORY  OF  SUN  SPOTS. 


225 


than  of  his  atmosphere,  though  of  a vaporous  or  cloud- 
like texture. 

It  has  been  demonstrated  by  actual  experiments  that 
the  photosphere  is  much  hotter  than  either  the  pen- 
umbra or  nucleus.  The  spots  themselves,  as  Henry, 
Secchi,  Langley,  and  others  have  shown,  certainly 
radiate  to  us  less  heat  than  the  general  surface  of  the 
sun.  According  to  the  elaborate  determinations  of 
Langley,  the  umbra  of  a spot  emits  about  fifty-four  per 
cent,  and  the  penumbra  about  eighty  per  cent  as  much 
heat  as  a corresponding  area  of  the  photosphere.* 
This  shows  that  the  heat  of  the  photosphere  is  not  pro- 
duced by  conduction  or  convection  from  the  cooler 
regions  below,  and  consecpiently  must  come  from  with- 
out. This  photosphere  is  the  fountain  of  all  the  sun’s 
radiations,  and  must  of  necessity  be  the  portion  cooled 
most  rapidly.  It  must,  therefore,  have  an  ample  source 
of  supply  independent  of  the  internal  heat  of  the  sun. 

There  seems  but  one  conclusion  possible,  and  that  is 
that  the  sun’s  loss  by  radiation  is  supplied  from  without. 
Whence  can  it  come  ? Only  from  other  suns  in  a per- 
petual round.  The  universal  ether  is  proved  to  be  cap- 
able of  conveying  impulses  of  light  and  heat  not  only 
in  opposite,  but  in  all  possible  directions  at  the  same 
time.  The  sun’s  light  and  heat  leave  that  luminary  by 
means  of  this  ether.  Can  we  doubt  that  they  return 
by  the  same  medium? 

That  the  planets  are  a family  group  and  the  sun  their 
father  is  not  so  much  a figure  of  rhetoric  as  a literal  fact. 
There  are  many  things  looking  toward  a common  origin 
and  of  course  a common  nature  for  the  whole  solar  sys- 
tem, but  not  a common  condition  at  the  present  time. 


15 


* “ The  Sun,”  by  Young,  page  159. 


226 


SUN  SPOTS. 


Now  the  earth  and  all  the  other  planets  have  this 
property  in  common ; all  the  heat  lost  by  them  is  radi- 
ated from  their  outer  surfaces,  and  all  the  heat  received 
by  them  to  supply  the  loss  and  keep  up  the  equilibrium 
is  received  .at  the  surface  from  the  sun  and  other  celes- 
tial bodies.  Analogy  would  teach  us  the  same  thing  is 
true  of  the  sun,  if  only  we  could  find  any  adequate 
source  from  which  this  heat  could  come.  However 
great  may  be  the  difficulty  in  finding  such  a source  out- 
side of  the  sun,  the  difficulty  is  augmented  to  an  im- 
possibility, if  we  look  for  such  a source  in  the  sun’s  in- 
terior. I have  discussed  this  subject  fully  in  another 
place  and  have  endeavored  to  show  that  there  is  no  lack 
of  abundant  supplies  of  light  and  heat  accessible  to  the 
sun  to  supply  all  his  loss  by  radiation. 

It  is  universally  conceded,  in  view  of  the  immense 
amount  of  heat  given  off,  that  the  sun,  if  unsupplied 
from  within  or  from  without,  would  cool  down  with  a 
rapidity  proportioned  to  the  loss.  It  would  only  be  a 
question  of  time  and,  according  to  the  best  authorities, 
a brief  time  at  that,  when  the  sun  would  be  so  far  cooled 
down  as  to  render  the  earth  uninhabitable.  * 

We  will  endeavor  to  gain  an  idea  of  the  condition  of 
things  in  the  sun  by  transferring  the  scene  for  a few 
minutes  to  the  earth.  Let  us  imagine  the  earth  to  be 
surrounded  on  all  sides  by  a hollow  sphere  thickly 
studded  with  suns  as  hot  as  ours  and  capable  of  raising 
the  whole  body  of  the  earth  to  an  equal  temperature. 
What  would  take  place  ? 

In  the  first  place  all  organic  substances,  including 
mineral  coal  and  oils,  would  flash  into  one  vast  confla- 
gration, equal  in  grandeur  to  the  apocalyptic  vision. 


* Newcomb’s  “Popular  Astronomy,”  page  518. 


A NEW  THEORY  OF  SUN  SPOTS. 


227 


The  resulting  forms  would  be  mainly  carbon  dioxide,  or 
carbonic  acid  gas,  and  water  in  the  form  of  steam.  As 
the  heat  continued  to  increase,  this  steam,  together  with 
all  the  water  in  all  the  rivers,  lakes  and  oceans  also  con- 
verted into  steam,  would  be  decomposed;  and  the  im- 
mense volumes  of  hydrogen  and  oxygen,  thus  liberated, 
would  mount  skyward,  increasing  our  atmosphere  to  an 
enormous  extent.  Not  only  this,  but  all  the  oxidized 
earths  and  metals  would  be  decomposed  and  the  liber- 
ated oxygen,  heated  to  a degree  far  beyond  the  point  of 
chemical  dissociation,  would  be  added  to  the  atmosphere, 
still  farther  increasing  its  enormous  volume.  As  if  there 
were  not  already  gases  enough  in  this  atmosphere,  the 
ever  increasing  heat  would  first  fuse  and  then  volatilize 
the  iron,  copper,  zinc,  and  probably  all  the  metals,  un- 
less we  except  platinum.  The  most  refractory  substances, 
such  as  silicon  and  platinum  would  probably  be  fused, 
and  lastly  would  come  the  cataclysmic  change  in  the  de- 
composition of  the  whole  volume  of  carbon  dioxide  into 
its  elements,  the  oxygen  joining  the  vast  volume  of  the 
gases,  and  the  carbon,  in  the  form  of  incandescent  vapor 
or  of  impalpable  atomic  dust,  descending  gently  in 
flocculent  clouds  of  fire  throughout  the  whole  expanded 
atmosphere.  When  these  fiery  vapors  had  settled  down 
to  loose  contact  with  the  molten  nucleus  still  remaining, 
they  would  form  a photosphere  to  the  earth  entirely 
similar  to  that  of  the  sun. 

This  carbon  vapor,  or  impalpable  white-hot  atomic 
dust,  would  at  once  know  and  assume  its  proper  place, 
intermediate  between  the  pure  transparent  gases  above 
and  the  liquid  silicon  and  more  refractory  metals  com- 
posing the  core,  as  the  receiver  and  radiator  of  the  in- 
tense heat  of  these  surrounding  suns.  The  transforma- 


228 


SUN  SPOTS. 


tion  would  now  be  complete.  The  earth  would  be,  in 
all  respects,  a little  sun. 

This  was  probably  once  the  condition  of  our  earth, 
but  it  has  now  cooled  down  so  as  to  become  the  lit 
abode  of  plants  and  animals,  and  even  of  frost  and 
snow.  And  yet  not  a particle  of  its  heat  has  ever  been 
lost.  While  our  earth  has  been  cooling,  some  other 
world  or  worlds  have  been  warmed  into  fruitfulness  as 
the  theatres  for  animal  and  vegetable  life ; or  if  suns 
were  needed  in  the  grand  economy,  the  heat  given  off  by 
our  earth  has  helped  to  kindle  other  suns,  or  still  more 
probably,  the  heat  given  out  by  our  earth  in  cooling 
has  been  replaced  by  tangential,  rotary  and  gravitative 
forces  with  other  forms  of  energy  at  work  on  the  sur- 
face and  in  the  interior  of  our  globe.  Whatever  dispo- 
sition has  been  made  of  the  intense  heat  which  at  one 
time  lkpiefied,  if  it  did  not  volatilize,  the  substance  of 
our  earth,  two  things  may  be  affirmed  with  absolute 
certainty : One  is  that  all  this  heat  is  somewhere  and 
in  some  form  conserved,  and  the  other  is  that  it  is  all  in 
active  operation,  which  is  merely  reaffirming  its  contin- 
ued existence,  for  energy  without  action  we  have  seen 
to  be  impossible. 


CHAPTER  III. 


THE  SUN’S  HEAT  DERIVED  FROM  THE  ETHER,  AND 

NOT  FROM  HIS  INTERIOR  — CAUSE  OF  SUN  SPOTS. 

A golden  axle  did  the  work  uphold, 

Gold  was  the  beam,  the  wheels  were  orbed  with  gold, 

The  spokes  in  rows  of  silver  pleased  the  sight, 

The  seat  with  parti-colored  gems  was  bright ; 

Apollo  shined  amid  the  glare  of  light.  — Ovid. 

"TTTHAT  we  have  imagined  in  the  earth  is  exactly 
V V what  we  find  to  be  the  existing  state  of  things  in 
the  sun.  As  the  carbon  vapors  composing  the  photo- 
sphere radiate  all  the  heat  which  leaves  the  sun,  it  must 
be  cooled  the  most  rapidly  of  any  part;  and,  as  it  is 
always  the  hottest  part  of  the  sun,  it  certainly  cannot 
derive  its  heat  from  the  interior  and  cooler  portions. 
Consequently  it  must  come  from  without ; from  the  sur- 
rounding ether. 

If  this  be  true,  then  the  sun  will  receive  his  heat  on 
all  sides,  and  the  poles  will  be  as  hot  at  least  as  at 
the  equator,  if  not  hotter.  This  we  find  to  be  the  case. 

It  maybe  asked  — in  fact  has  been  asked,  “If  the 
photosphere  is  the  hottest  part  of  the  sun,  why  does  it  not 
by  conduction  raise  the  whole  interior  to  the  same  tem- 
perature ? ” I reply : The  photosphere  has  other  uses  for 
its  surplus  head  in  warming  the  earth  and  other  worlds 
and  suns.  Being  in  contact  with  the  ether,  it  is  much 
easier  to  part  with  its  heat  by  radiation  than  by  the 
slower  process  of  conduction  through  gaseous  media  to 

229 


230 


SUN  SPOTS. 


the  sun’s  interior.  At  all  events,  fact  is  fact,  whether 
it  suits  our  ideas  or  not. 

Affirmatively,  it  appears  to  me  highly  probable  that 
the  sun  s])ots  are  produced  by  a relative  lowering  of  the 
temperature  of  the  photosphere  in  the  zones  where  the 
spots  occur.  As  it  is  held  by  all  the  best  authorities 
that  the  photosphere  is  composed  of  intensely  heated 
vapors  (I  think  carbon  vapors),  in  the  form  of  clouds, 
it  would  seem  most  natural  that  these  clouds  when 
slightly  cooled,  should  first  be  converted  into  a line 
incandescent  mist,  then  to  fiery  rain,  hail  or  snow  (if  we 
may  use  old  words  with  new  meanings),  according  to 
the  nature  of  the  element  or  elements  composing  the 
sun’s  photosphere.  In  this  way  large  regions  of  the 
photosphere,  if  sufficiently  cooled,  would  fall  to  the  sun 
in  the  form  of  solar  rain,  hail  or  snow,  or,  as  I think,  in 
the  form  of  impalpable  carbon  dust,  leaving  the  inner, 
cooler  and  darker  surface  of  the  sun  uncovered,  just  as 
clouds  in  our  atmosphere,  when  condensed,  descend  in 
the  form  of  rain  and  snow,  and  leave  the  surface  of  the 
earth  previously  covered  with  clouds  open  to  the  inspec- 
tion of  the  inhabitants  of  other  worlds. 

The  extent  and  duration  of  these  spots  would  be  as 
variable  as  our  “ spells”  of  weather,  being  produced  by 
similar  causes,  viz.:  variations  of  temperature  in  the 
enveloping  atmospheres  and  clouds  of  the  earth  and 
sun  respectively.  If  our  earth,  like  Jupiter,  were 
always  covered  by  silver-lined  clouds,  with  the  lining 
on  the  outside,  and  if  only  occasional  rifts  occurred, 
exposing  the  earth’s  surface,  the  inhabitants  of  other 
planets  would  call  them  earth  * spots,  and  the  fleecy 


* Unless  the  inhabitants  of  other  worlds  have  other  names  for  our  planet. 


CAUSE  OF  SUN  SPOTS. 


231 


clouds  would  form  a mild  kind  of  mundane  photo- 
sphere. 

The  variations  in  the  temperature  of  our  atmosphere 
are  easily  accounted  for  by  the  extremely  diversified 
aspects  in  which  the  earth  presents  herself  to  the  sun, 
the  source  of  her  heat,  owing  to  the  variety  in  her  mo- 
tions and  the  inclination  of  her  axis.  But  in  the  case 
of  the  sun,  if  the  theory  that  he  receives  his  heat  equally 
from  all  parts  of  the  celestial  concave  is  correct,  then 
his  cloudy  envelope  at  least  ought  to  be  in  a state 
of  comparative  rest.  Such  we  find  to  be  the  case. 
Only  two  narrow  belts,  one  on  each  side  of  the  sun’s 
equator,  are  affected  by  sun  spots.  Of  course  so  unsta- 
ble a thing  as  an  ocean  of  incandescent  hydrogen, 
mingled  with  other  gases,  which  occupy  the  higher 
regions  of  the  sun’s  atmosphere,  could  hardly  be  ex- 
pected to  be  entirely  quiescent  under  any  circumstances. 
On  the  contrary,  the  most  violent  convulsions  may  be 
expected  in  the  upper  regions  of  the  sun’s  atmosphere. 
That  this  restful  condition  prevails  in  the  sun’s  photo- 
sphere (not  in  his  chromosphere  and  corona),  seems 
probable  from  the  following  considerations : 

I believe  every  writer  without  exception  considers 
'the  photosphere  to  be  of  vaporous  or  cloud-like  texture. 
Consequently  it  would  yield  with  the  greatest  readiness 
to  any  disturbing  force  affecting  it  or  the  gaseous 
medium  in  which  it  floats.  But  the  sun  spots,  which  all 
admit  to  be  cavities  in  the  photosphere,  remain  not  only 
for  days  and  weeks,  but  often  for  months  without  being 
obliterated.  The  comparatively  restful  condition  of 
the  sun’s  cloudy  envelope  forms  no  slight  corroboration 
of  the  truth  of  this  theory. 


232 


SUN  SPOTS. 


CAUSE  OF  SUN  SPOTS. 

We  will  now  address  ourselves  to  an  attempt  to 
ascertain  the  cause  of  sun  spots. 

I attribute  the  cooling  of  the  portions  of  the  sun’s 
photosphere,  comprised  in  the  maculated  belts  (by 
which  large  fields  of  fiery  clouds  are  precipitated,  and 
the  sun’s  .surface  uncovered),  to  the  shadows  cast  upon 
the  sun  by  Jupiter  and  the  other  planets.  If  the  source 
of  the  sun’s  heat  is  the  whole  celestial  concave,  then 
these  planetary  bodies  and  their  satellites,  mainly  lo- 
cated within  the  limits  of  the  zodiac,  are  the  only 
bodies  that  could  intercept  any  portion  of  the  waves 
inundant  on  the  sun. 

Of  course,  the  shadows  cast  by  the  heavenly  bodies 
are  very  different  from  those  we  are  familiar  with  on  the 
earth.  The  former  are  dynamic,  or  rather  anti-dynamic. 
They  are  simply  the  aggregate  of  the  shadows  of  the 
particles  composing  these  bodies.  I hope  no  one  will 
decide  authoritatively  that  the  effect  of  these  shadows 
combined  must  of  necessity  be  infinitesimal,  while  he 
admits  that  a force  which  we  call  gravitation  is  exerted 
between  the  sun  and  these  same  bodies,  which  is  by  no 
means  infinitesimal.  In  fact,  we  claim  that  the  energy 
intercepted  from  the  sun  by  these  bodies  is  identical 
with  gravitation.  It  consists,  as  we  conceive,  of  waves 
of  mechanical  force,  turning  to  heat  when  intercepted, 
coming  from  the  celestial  concave,  which  would,  if  un- 
intercepted, make  the  equatorial  regions  of  the  sun 
equally  hot  with  his  poles,  but  being  intercepted,  ex- 
pends itself  in  bending  the  tangential  motion  of  the 
planets  into  the  curved  lines  of  their  orbits.  In  conse- 
quence of  the  diversion  of  this  intercepted  energy  to 


CAUSE  OF  SUN  SPOTS. 


233 


the  purposes  of  gravitation,  the  sun  experiences  a defi- 
ciency, greatest  near  his  equator,  where  the  intercepted 
rays  woulj  have  been  vertical,  and  shading  out  toward 
the  poles. 


CHAPTER  IV. 


ARGUMENT  FROM  THE  UNEQUAL  ROTATION  OF  THE 
SUN  SPOTS. 


Thou  chief  star, 


Centre  of  many  stars  which  mak’st  our  earth 

Endurable  and  temperest  the  hues 

And  hearts  of  all  who  walk  within  thy  rays! 

Sire  of  the  seasons!  Monarch  of  the  climes, 

And  those  who  dwell  in  them ! for  near  or  far, 

Our  inborn  spirits  have  a tint  of  thee, 

Even  as  our  outward  aspects : thou  dost  rise, 

And  shine,  and  set  in  glory.  — Byron. 

IIE  sun  at  his  equator  revolves  on  his  axis  in  about 


-L  twenty-five  days.  At  twenty  degrees  north  and 
south  latitude  he  appears  to  revolve  in  twenty-five 
and  three-fourths  days;  at  thirty  degrees  in  twenty- 
six  and  a half  days,  and  at  forty-five  degrees  in 
about  twenty-seven  and  a half  days.  IIow  does  this 
accord  with  the  theory  here  advanced?  If  the  fiery 
clouds  composing  the  photosphere  are  relatively  cooler 
at  and  near  the  equator,  then  a circulation  will  be 
set  up,  analogous  to  the  circulation  of  the  cloud-bearing 
winds  on  the  earth.  But  as  the  zones  are  reversed 
so  will  be  the  circulation.  The  cooler  portions  of 
the  photosphere  will  sink  down  and  how  out  as  the 
under  currents  from  the  equatorial  regions  of  the  sun 
toward  his  poles.  These  out-flowing  currents  will  leave 
the  equatorial  regions  with  the  rotary  velocity  of  the 
nucleus,  but  will  be  continuously  retarded  by  friction 


234 


UNEQUAL  ROTATION  OF  THE  SUN  SPOTS. 


235 


till  they  reach  the  polar  regions,  by  which  time  they 
will  have  accommodated  themselves  to  the  slower  mo- 
tion of  the  nucleus  at  the  poles.  By  intermingling  and 
coming  to  the  surface,  these  currents  will  also  by  this 
time  have  acquired  the  higher  temperature  of  the  polar 
regions  where  no  shadows  are  cast  upon  the  sun.  They 
will  then  start  on  their  return  toward  the  equator  as 
the  upper  and  hotter  currents,  but  with  the  compara- 
tively slow  rotary  motion  of  the  polar  regions.  As 
these  currents  appoach  the  equator,  they  will  lag  be- 
hind the  motion  of  the  body  of  the  sun  most  at  first, 
but  will  become  gradually  accelerated  as  they  approach 
the  equator,  till,  on  arriving  in  the  equatorial  regions, 
they  will  have  regained  the  rotary  velocity  of  the  nu- 
cleus at  the  equator,  precisely  as  the  cloud-bearing 
winds  on  the  earth  are  alternately  accelerated  and 
retarded  in  their  rotary  motion  in  accommodating  them- 
selves in  turn,  now  to  the  swift  motion  of  the  equato- 
rial, and  then  to  the  slow  motion  of  the  polar  regions 
of  the  earth,  only  in  a reversed  order.  This  circulation, 
on  the  supposition  of  a relatively  cooler  zone  extending 
for  some  distance  north  and  south  of  the  equator,  is 
inevitable.  The  result  will  be  that  the  photosphere  in 
the  equatorial  regions  will  keep  pace  with  the  body  of 
the  sun.  But  north  and  south  of  the  equator  the  upper 
and  visible  portion  of  the  photosphere,  in  which  the 
spots  are  seen,  will  lag  behind  in  its  rotary  motion  in- 
creasingly from  the  equator  toward  the  poles. 

The  result  of  these  currents  must  inevitably  be  that 
the  photospheric  envelope  of  the  sun  will  keep  pace 
with  his  body  at  the  equator,  performing  a revolution 
in  twenty-five  days,  while  those  portions  north  and 
south  of  the  equator,  with  their  included  spots,  will  be 


236 


SUN  SPOTS. 


retarded,  and  will  take  longer  time  to  perform  a revo- 
lution, just  in  proportion  to  their  solar  latitude.  This 
is  exactly  what  has  been  found  to  be  the  case  by  the 
patient  and  careful  observations  of  Carrington  from 
1853  to  1861  * 

I can  see  no  probable,  nor  even  possible,  explanation 
of  the  slower  motion  of  the  sun  spots  north  and  south 
of  the  equator,  except  on  the  supposition  of  such  a cir- 
culation as  I have  described  ; and  such  a circulation  can 
only  be  produced  by  a cooler  zone  at  and  near  the 
equator. 

We  call  these  grand  movements  of  the  photospheric 
and  penumbral  clouds  currents , for  want  of  a better 
term.  If  I am  correct,  they  constitute  very  slow  mass 
movements  of  the  whole  vast  volume  of  the  sun’s 
cloudy  envelope. 

I have  elsewhere  shown  that  owing  to  the  fact  that 
the  sun  receives  his  heat  almost  equally  on  all  sides, 
there  are  no  great  inequalities  in  the  temperature  of 
different  parts  of  the  solar  surface,  and  consequently  no 
violent  currents,  as  upon  the  earth.  This  is  proved  by 
the  somewhat  permanent  character  of  the  spots.  These 
generally  remain  for  some  days,  and  often  for  weeks 
and  months,  with  but  slight  alterations  in  form.  If 
violent  winds  were  sweeping  over  the  face  of  the  sun, 
the  spots,  being  of  a cloudy  nature,  would  be  swept 
away  as  soon  as  formed.  The  flashes  and  streamers 
sometimes  observed  are  generally  considered  to  be 
auroral,  and  not  a transference  of  actual  matter. 

Still,  there  are  undoubtedly  the  slow  currents  of  cir- 
culation I have  described.  In  general,  they  are  divided 
into  upper  and  lower  currents,  as  in  our  atmosphere, 


See  “The  Sun,”  by  Young,  pages  133  and  134. 


UNEQUAL  ROTATION  OF  THE  SUN  SPOTS. 


237 


only  reversed,  as  the  cooler  and  hotter  zones  are  re- 
versed. But,  as  in  onr  atmosphere,  so  in  the  sun,  these 
currents  sometimes  clash  and  become  mixed. 

In  the  sun’s  northern  hemisphere,  the  currents,  both 
upper  and  lower,  relatively  to  the  solar  surface  as  seen 
by  us,  are  northwest  and  southeast.  It  will  be  remem- 


s 

Fig.  13. 


bered  that  the  sun’s  apparent  rotary  motion,  as  seen  by 
us , is  from  east  to  west.  These  upper  and  lower  cur- 
rents will  be  parallel  with  each  other,  but  in  opposite 
directions. 

If  the  arrows  represent  different  intermingling  cur- 
rents, it  is  plain  that,  should  a sun  spot  be  located 


238 


SUN  SPOTS. 


between  the  currents  a b and  c d , their  edges  would 
revolve  from  left  to  right,  like  the  hands  of  a watch ; 
the  same  between  e f and  g h ; but  between  the  cur- 
rents c d and  e f,  and  also  between  g h and  i j , they 
would  revolve  from  right  to  left.  This  we  find  to  be 
the  case,  exhibiting  occasionally  the  appearance  of 
cyclones,  but  revolving  sometimes  in  one  direction,  and 
at  others  in  an  opposite  one.  Can  this  be  accounted 
for  on  any  other  hypothesis  ? 


Fig.  14.— Cyclonic  Sun  Spot,  by  Secchi. 


The  only  writer,  so  far  as  I am  aware,  who  lias 
attempted  to  account  for  the  cyclonic  character  of  the 
spots  is  the  ingenious  French  writer,  Faye.  But  his 
theory  would  require,  not  some  only,  but  all , the  spots 
to  lie  vortical,  and  would  further  require  all  spots  north 
of  the  sun’s  equator  to  rotate  from  right  to  left,  and 
all  south  of  the  equator,  from  left  to  right  ; whereas,  it 
is  well  known  that  only  a small  proportion  of  the  spots 
rotate  at  all ; and  of  those  which  do,  some  rotate  in  one 


UNEQUAL  ROTATION  OF  THE  SUN  SPOTS. 


239 


direction,  and  some  in  the  other,  in  the  same  hemi- 
sphere. Still,  the  theory  is  a good  one,  and  all  that  is 
necessary  is  to  make  the  spots  conform  to  it. 


CHAPTER  Y. 


DISTRIBUTION  OF  SUN  SPOTS. 

Alcyone  shines  with  a force  of  twelve  thousand  suns.  And  then 
we  have  suns  themselves  combined  into  systems  of  all  sizes  and 
shapes  — systems  of  two,  of  three,  of  many,  of  millions  — firma- 
ments which,  under  the  name  of  nebulae,  are  the  last  generalization 
and  most  stupendous  variety  of  modern  discovery;  sometimes  rolled 
up  into  spheres;  sometimes  gathered  into  circular  or  elliptic  rings: 
now  fan  shaped ; now  like  an  hour  glass ; now  broad  wheels  of  com- 
pacted suns,  large,  glittering,  and  sublime  enough  to  under-roll  the 
chariot  of  Omnipotence. — Pater  Mundi. 

SUCH  is  a glowing  description,  not  altogether  ima- 
ginative, of  the  suns  of  space  by  one  of  the  most 
eloquent  writers  of  modern  times.  There  is  but  one  of 
this  innumerable  host  that  we  can  examine  with  any- 
thing like  exactness.  But  from  this  one  we  can  learn 
more  than  from  all  the  rest  combined. 

One  of  the  most  interesting  facts  in  regard  to  the 
“wandering  isles  of  night,”  called  sun  spots,  is  their 
peculiar  and  permanent  manner  of  distribution  upon 
the  solar  surface. 

We  have  seen  that  they  are  confined  almost  entirely 
within  two  parallels,  thirty  degrees  north  and  south  of 
the  sun’s  equator,  diminishing  in  frequency  toward  the 
northern  and  southern  boundaries  of  these  belts,  and 
also  toward  the  equator. 

Figure  15  on  the  opposite  page  represents  the  sun 
with  the  plane  of  his  equator  inclined  to  that  of  the 

240 


Fig.  15. 


DISTRIBUTION  OF  SUN  SPOTS. 


241 


S ty 

| 

iMil  I 


s/h  ■# 


242 


SUN  SPOTS. 


ecliptic,  or  plane  of  the  earth’s  orbit,  at  an  angle  of 
seven  and  one-quarter  degrees,  together  with  the  planes 
of  the  four  other  planets  nearest  the  sun. 

The  planes  of  the  three  exterior  planets  are  omitted 
for  the  triple  reason : 1,  because  from  their  great  dis- 
tance they  can  have  but  very  little  influence  upon  sun 
spots;  2,  in  a small  figure  the  planes  would  be  so 
crowded  as  nearly  to  obliterate  each  other ; and,  3,  be- 
cause the  principle  can  be  as  well  illustrated  by  the  five 
nearer  planets  as  by  all.  It  will  be  seen  that  during 
one-half  of  the  years  respectively  of  each  of  the  planets, 
their  orbits  are  above,  and  during  the  other  half  below, 
the  sun’s  equator.  As  the  planetary  years  differ  greatly 
in  length,  the  planets,  at  a rough  average,  will  at  all 
times  be  distributed  in  nearly  equal  proportions  north 
and  south  of  the  sun’s  equator,  as  well  as  in  their  direc- 
tions from  the  sun.  The  dotted  lines  will  represent 
those  parallels  on  the  sun  to  which  Mercury,  Jupiter, 
and  Venus  respectively  will  be  vertical  at  their  extreme 
northern  and  southern  limits.  They,  of  course,  repre- 
sent the  lines  on  which  these  planets  respectively  would 
be  most  influential  in  producing  sun  spots  at  these 
times.  But  the  planets  remain  at  their  extremes  of 
north  and  south  latitude  for  a short  time  only,  and 
during  each  revolution  become  in  turn  twice  vertical  to 
the  equator  and  every  parallel  on  the  sun  between  these 
extremes. 

One  only  of  the  planets,  Mercury,  but  a very  influ- 
ential one  on  account  of  his  proximity,  ever  extends 
his  north  and  south  latitude  sufficiently  to  make  his 
shadow  vertical  to  the  centres  of  the  maculated  belts, 
and,  of  course,  only  for  a short  time  at  each  revolution. 
All  the  other  planets,  including  those  omitted  from  the 


DISTRIBUTION  OF  SUN  SPOTS. 


243 


figure,  oscillate  from  one  side  of  the  sun’s  equator  to 
the  other  within  much  narrower  limits. 

This  would  indicate  that  the  average  of  all  the 
shadows  cast  by  all  the  planets  must  be  densest  at  and 
near  the  equator,  fading  out  in  both  directions;  and 
the  sun  spots,  if  they  knew  how  to  behave  themselves, 
would  be  most  numerous  at  and  near  the  equator,  and 
would  shade  out  each  way  to  about  their  present  boun- 
daries. 

But  as  the  spots  will  not  conform  to  our  theories,  let 
us  see  if  our  theory  can  be  accommodated  to  the  spots. 

It  matters  not  at  what  point  we  start  in  to  accom- 
pany the  currents  in  the  pliotospheric  and  umbral 
clouds,  which,  as  we  believe,  circulate  from  the  equator 
to  the  poles  and  back  again.  We  will  therefore  join 
them  in  imagination  at  the  poles,  or  (confining  ourselves 
for  the  present  to  the  sun’s  northern  hemisphere)  at  the 
north  pole.  Here  the  photosphere  is  exposed  to  the 
hottest  of  the  solar  skies,  and  becomes  heated  to  the 
highest  temperature  which  these  clouds  ever  attain. 
Thus  heated  they  start  toward  the  equator,  but  with 
the  very  slow  rotary  motion  of  the  circumpolar  regions 
of  the  sun.  The  result  is  that  they  will  lag  behind  the 
body  of  the  sun  during  their  whole  progress  from  the 
pole  to  the  equator,  and  when  the  currents  reach  the 
maculated  belts,  the  spots  will  also  lag  behind  just  in 
proportion  to  their  solar  latitude.  When  these  cur- 
rents reach  the  northern  boundary  of  the  maculated 
belt,  to  the  centre  of  which  Mercury  is  vertical  once  in 
every  eighty-eight  days,  they  begin  to  feel  the  cooling 
influence  of  the  planetary  shadows,  and  the  spots  com- 
mence to  appear,  though  sparsely  at  first. 

I believe  there  is  no  dissent  among  scholars  as  to  the 


244 


SUN  SPOTS. 


belief  that  even  what  are  called  the  pores  on  the  sun’s 
surface  are  intensely  hot  and  brilliantly  white,  and  that 
they  only  appear  dark  by  contrast  with  the  still  hotter 
and  more  brilliant  granules  and  faculse  of  the  sun. 

It  is  well  known  that  almost  the  whole  surface  of 
the  sun  is  made  up  of  these  granules  and  pores  — the 
pores  being  in  the  proportion  of  four  to  one  of  the 
granules  and  much  cooler  than  the  latter.  If  the  mat- 
ter of  both  is  the  same,  as  can  hardly  be  doubted,  then 
the  whole  surface  of  the  sun  is  nicely  balanced  on  the 
dividing  line  between  the  granular  and  porous  condi- 
tions. A slight  increase  in  temperature  would  convert 
the  pores  into  granules  and  a slight  lowering  would 
convert  the  granules  into  pores. 

To  continue  our  imaginary  journey : When  these 
currents  in  their  southward  progress  have  reached  the 
parallel  of  twenty  degrees,  the  spots  become  most  nu- 
merous. As  they  approach  the  equator,  the  spots  again 
decrease,  till  at  about  ten  degrees  they  almost  entirely 
disappear. 

On  approaching  the  equator  the  currents,  being  now 
considerably  cooled,  dive  down  to  the  sun’s  nucleus  and 
commence  the  return  voyage  as  the  undercurrent 
toward  the  pole.  This  journey  is  without  incident,  ex- 
cept that  the  upper  and  lower  currents  sometimes  clash 
and  intermingle  to  a certain  degree,  as  in  the  cloud- 
bearing atmospheric  currents  on  the  earth,  and  thus 
cause  occasional  cyclonic  action  in  the  spots.  These 
lower  currents  are  but  slightly  cooler  than  the  upper 
ones,  but  sufficiently  so  to  make  their  substance,  like 
the  pores,  appear  black  by  contrast. 

This  is  the  place  to  state  that,  according  to  the 
theory  here  advanced,  the  sun  spots  do  not  extend 


DISTRIBUTION  OF  SUN  SPOTS. 


245 


downward  to  the  nucleus  of  the  sun,  hut  only  to  this 
blackened  undercurrent  of  umbral  clouds.  We  are 
now  prepared  to  consider  the  question : Since  the 
shadows  of  the  combined  planetary  system  are  densest 
on  and  near  the  equator,  why  should  not  the  spots  be 
most  numerous  in  this  part  of  the  sun  ? 

We  reply  that,  at  the  solar  equator,  and  for  some  dis- 
tance north  and  south  of  the  same,  this  celestial  Niagara 
of  glowing  carbon  clouds,  inconceivably  hot,  notwith- 
standing their  slight  comparative  cooling  by  the  plane- 
tary interceptions,  dives  down  to  an  unknown  depth 
and  then  turns  northward  and  southward  toward  the 
poles.  Now  suppose  an  ambitious  pore  on  the  upper 
surface  of  this  perpendicular  downward  current  should 
attempt  to  expand  itself  into  a magnificent  sun  spot,  the 
downward  current  would  swallow  it  up  before  it  could 
be  formed.  Besides  this;  if  a sun-spot  opening  could 
be  formed  in  the  upper  surface  of  this  downward  cur- 
rent, it  would  not  be  based,  as  in  the  other  cases,  upon 
the  blackened  surface  of  the  under  current,  which  is  not 
yet  fully  formed.  Thus  a spot,  if  it  existed  on  or  near 
the  equator,  would  seldom  be  visible  for  want  of  a 
darker  background. 

It  seems  certain  that  the  edges  of  some  of  the  sun 
spots,  under  the  influence  of  some  mysterious  process, 
take  on  forms  of  grace  and  beauty  somewhat  resem- 
bling arborescent  frost  wrork  on  glass,  finely  depicted  in 
Prof.  S.  P.  Langley’s  illustrations,  Figs.  18  and  21,  and 
also  in  Figs.  16  and  IT. 

We  may  well  believe  that  between  the  parallels  of 
ten  degrees  and  thirty  degrees  the  restful  condition 
of  the  photosphere,  under  the  cooling  influence  of  the 
planetary  shadows,  is  highly  favorable  to  the  formation 


246 


SUN  SPOTS. 


first  of  enlarged  {lores  developing  into  the  large  areas 
of  precipitation  known  to  us  as  sun  spots,  and  that  the 
tumult  and  rush  of  the  downpour  at  and  near  the 
equator  are  equally  unfavorable,  so  that  spots  here  will 
be  correspondingly  rare; 

Thus  we  see  that,  though  the  planets  do  not,  and,  in 
the  nature  of  things,  cannot,  cast  their  shadows  in  two 
zones  corresponding  to  the  maculated  belts,  still,  ow- 


Fig.  16.— Sun  Spot  of  July  31,  1869. 

ing  to  the  peculiar  nature  of  the  circulation  in  the  plio- 
tospheric  and  urnhral  clouds,  in  connection  with  the 
planetary  shadows,  the  double-belted  distribution  is 
effected. 

It  may  be  replied : What  proof  have  wc  of  the  ex- 
istence of  this  circulation ? We  answer:  Two  undenia- 
ble facts.  One  is  the  lagging  motion  of  the  sun  spots, 
and  the  other,  their  occasional  cyclonic  action.  I know 


DISTRIBUTION  OF  SUN  SPOTS. 


247 


of  no  possible  way  of  accounting  for  either  of  these 
phenomena  except  by  such  a circulation. 

Another  fact  is  equally  convincing.  If  it  be  con- 
ceded, or  has  been  proved,  that  the  sun  receives  his  sup- 
ply of  heat  from  the  stellar  concave  through  the  ether, 
then  it  is  as  certain  that  the  planets  must  intercept  a 
portion  of  the  energy  which  supplies  this  heat,  as  that  a 
screen  held  between  a lighted  candle  and  a wall  must  in- 
tercept a portion  of  the  light  of  the  former  from  the  latter. 
It  is  just  as  certain  that,  if  motion,  or  energy  convertible 
into  heat,  be  intercepted  from  the  equatorial  region  of 
the  sun,  a circulation  in  the  fleecy  clouds  of  the  photo- 
sphere and  umbra  must  be  produced. 

We  confess  that  it  seems  presumptuous  for  man  with 
his  limited  powers  to  intrude  “ where  angels  might  fear 
to  tread.”  We  stand  awe-struck  in  the  presence  of 
this  king  of  day,  and  hardly  dare  admit  to  ourselves 
that  we  are  able  to  penetrate  the  profound  secrets  of 
his  being.  But,  if  we  are  not  to  study  the  sun,  why  is 
he  allowed  to  exhibit  himself  to  us  in  all  his  glorious 
pomp,  and  why  were  we  endowed  with  the  powers  and 
the  desire  to  investigate  his  awful  mysteries  ? 


CHAPTER  VI. 


PERIODICITY  OF  SUN  SPOTS. 

Nature  is  one  eternal  circle. — Percival. 

THE  sun  spots  increase  and  diminish  in  fairly,  but 
not  sharply,  defined  periods  of  about  11.111  years, 
according  to  Wolf. 

How,  all  the  planets  move  in  orbits  more  or  less 
elliptical.  It  is  manifest  that  the  nearer  any  planet  is 
to  the  sun  — that  is,  the  nearer  it  is  to  its  perihelion  — 
the  denser  will  be  the  shadow  cast  by  it  upon  the  sun. 
The  mass  of  each  planet,  divided  by  the  square  of  its 
distance,  will  express  its  relative  cooling  influence  upon 
the  sun.  Jupiter,  from  his  immense  mass  (being  three 
hundred  and  thirty-eight  times  that  of  the  earth,  and 
more  than  double  that  of  all  the  other  planets  com- 
bined), as  well  as  from  his  relative  distance  and  eccen- 
tricity of  orbit,  would  necessarily  dominate  in  the  mat- 
ter of  sun  spots.  Still,  he  will  sometimes  be  assisted, 
and  at  others  antagonized,  by  the  influence  of  the  other 
planets,  so  far  as  hastening  or  delaying  the  maximum 
periods  is  concerned. 

For  example,  every  forty-ninth  perihelion  of  Mer- 
cury, every  nineteenth  of  Venus,  every  twelfth  of  the 
Earth,  and  every  sixth  of  Mars,  will  very  nearly  syn- 
chronize with  those  of  Jupiter.  At  these  times  the 
maxima  will  probably  be  more  marked  ; at  others,  less 
so.  A.  Guillimin,  in  his  work,  u The  Sun,”  page  209, 


PERIODICITY  OF  SUN  SPOTS. 


24:9 


in  a note,  speaking  of  Warren  De  La  Rue,  Balfour 
Stewart,  and  Loewy’s  studies  in  relation  to  the  influ- 
ence of  Jupiter,  says : 

“They  appear  to  have  observed  that  when  one  of  these  planets 
passes  across  the  plane  of  the  sun’s  equator,  it  drags,  as  it  were,  the 
spots  into  the  equatorial  region  of  the  disc;  they  spread  toward  the 
poles,  on  the  contrary,  when  the  planets  pass  away  from  the  equatorial 
plane.” 

This  negative  cause  of  sun  spots,  through  cooling  by 
planetary  shadows,  as  well  as  their  distribution,  is  won- 
derfully confirmed  by  a writer  in  Belgravia,  No.  13, 
page  51,  without  knowing  or  intending  it,  thus : 

“But  it  was  reserved  for  the  patient,  day-by-day  watchers  and 
draughtsmen  of  our  time  to  discover  that,  as  Venus  rolls  in  her 
inclined  orbit  around  the  luminary,  the  spots  retreat  farther  from 
the  equator  as  the  planet  increases  her  solar  latitude;  in  other 
words,  that  there  is  a tendency  in  the  spots  to  locate  themselves  per- 
pendicularly under  the  planet. 

“Another  curious  fact  evolved  from  the  daily  chronicling  is  that 
when  Mercury  passes  between  Venus  and  the  sun,  the  spots  come 
forth  in  the  fullest  splendor,  and  there  is  more  than  a suspicion  that 
Mars,  in  conjunction  with  one  of  the  inferior  planets,  is  influential 
in  increasing  the  area  of  the  spottiness.” 

This  writer  might  have  added  that  Jupiter,  and  all 
the  other  planets,  in  proportion  to  their  respective 
masses  and  proximity  to  the  sun,  aid  in  producing  this 
“ spottiness,”  and  that  their  solar  latitude  influences,  if 
not  absolutely  determines,  the  latitude  of  the  spots. 

After  reading  these  extracts,  how  is  it  possible  to 
doubt  that  the  spots  are  produced  by  the  shadows  of 
these  and  the  other  planets  projected  on  the  sun  ? 

Adopting  Wolf ’s  periods  of  sun-spot  maxima  from 
1015  to  1870,  a period  of  two  hundred  and  fifty-five 
years,*  I have  copied  the  following  table,  exhibiting 


*See  “ The  Sun,”  by  Young,  page  148. 


250 


SUN  SPOTS. 


in  parallel  columns,  first,  the  dates  of  Jupiter’s  peri- 
helia ; second,  the  dates  of  the  corresponding  sun-spot 
maxima ; third,  the  intervals  between  successive  sun- 
spot maxima. 


Jupiter’s 

Perihelia. 

Sun  Spot. 
Maxima. 

Sun  Spot. 
Interval. 

Jupiter’s 

Perihelia. 

Sun  Spot. 
Maxima. 

Sun  Spot. 
Interval. 

1607.95 

1615.50 

1762.13 

1761.50 

11.20 

1619.81 

1626. 

10.50 

1773  99 

1769.70 

8.20 

1681.67 

1639.50 

13.50 

1785.85 

1778.40 

8.70 

1643.53 

1649. 

9.50 

1797.71 

1788.10 

9.70 

1655.39 

1660. 

11. 

1809.57 

1804.20 

16.10 

1667.25 

1675. 

15. 

1821.43 

1816.40 

12.20 

1679.11 

1685. 

10. 

1833.29 

1829.90 

13.5) 

1690.97 

1693. 

8. 

1845.15 

1837.20 

7.30 

1702.83 

1705.50 

12.50 

1857.01 

1848.10 

10.90 

1714.69 

1718.20 

12.70 

1868.87 

1860.10 

12. 

1726.55 

1727.50 

9.30 

1880.73 

1870.60 

10.50 

1738.41 

1750.27 

1738.70 

1750.30 

11.20 

11.60 

1881.70 

11.10 

The  average  interval,  according  to  Wolf,  is  11.111 
years,  while  the  Jovian  period  is  11.86.  This  resem- 
blance between  the  two  periods  has  been  sufficient  to 
attract  the  attention  of  every  writer  on  the  subject.  Still 
there  is  sufficient  discrepancy,  coupled  with  the  irregular- 
ity in  the  intervals  of  the  maximum  periods,  to  puzzle 
the  philosophers  and  baffle  all  attempts  to  bring  them 
into  any  certain  relation  to  the  perihelion  periods  of 
Jupiter.  Much  less  lias  anyone  attempted  to  point  out 
any  relation  of  cause  and  effect  between  the  two,  and 
still  less,  the  nature  of  that  cause. 

Though  the  Jupiter  of  astronomy  is  not  chargeable 
with  the  fickleness  and  follies  of  the  Jupiter  of  mythol- 
ogy, there  certainly  seems  to  be  a perverse  refusal  on 
the  part  of  the  former  to  scpiare  his  conduct  with  the 
periods  of  sun-spot  maxima.  Still,  rather  than  throw 
aside  as  worthless  so  interesting,  though  imperfect,  a cor- 


PERIODICITY  OF  SUN  SPOTS. 


251 


respondence,  as  all  writers  on  the  subject,  so  far  as  I 
know,  have  done,  I would  prefer  to  see  if  some  plan  of 
reconciliation  cannot  be  discovered. 

A preliminary  observation,  in  which  all  will  agree 
with  the  writer,  is,  that  the  investigation  of  this  subject 
properly  belongs  to  astronomers  only.  But  anyone  may 
offer  suggestions  to  be  taken  only  for  what  they  are 
worth. 

My  first  observation  then  is  that  sun  spots  per- 
tain wholly  to  what  may  be  called  solar  weather,  or 
changes  in  solar  temperature.  The  weather  in  the  sun, 
though  far  less  complicated  than  that  of  the  earth,  par- 
takes, to  some  extent,  of  the  same  nature,  and  that  na- 
ture precludes  the  possibility  of  that  exactness  in  calcu- 
lation, which  the  sublime  science  of  astronomy  has 
attained  in  regard  to  the  motions  of  the  heavenly  bodies. 

It  is  manifest  from  the  table  that  the  first  ten  sun- 
spot maximum  periods,  as  compared  with  the  corre- 
sponding perihelia  of  Jupiter,  all  occurred  after  Jupiter 
had  circled  through  the  whole,  or  nearly  the  whole,  of 
the  perihelion  half  of  his  orbit  and  had  retired  to  the 
neighborhood  of  his  aphelion,  or  even  beyond,  leaving 
in  his  wake,  according  to  the  theory  here  advocated,  a 
cold  streak  encircling  the  sun  once  every  twenty-five 
days.  If  “ coming  events  cast  their  shadows  before,”  it 
is  no  less  true  that  departing  events  leave  their  shadows 
behind. 

Though,  in  these  cases,  Jupiter  has,  for  about  six 
years  on  an  average,  been  streaking  the  body  of  the  sun 
like  the  cylinder  of  the  phonograph,  with  lines  of 
lower  temperature,  he  certainly  has  enjoyed  the  aid  of 
the  perihelion  periods  of  other  planets  in  bringing  out 
the  sun-spot  maxima.  In  the  cases  where  the  maxima 


252 


SUN  SPOTS. 


lag  behind  the  perihelia  of  Jupiter,  the  other  perihelia 
which  have  supplemented  his  work  have  followed  at  a 
respectful  distance  behind  those  of  the  former. 

From  1769  to  the  end  of  the  series  included  in  this 
table  nearly  the  same  process  is  repeated  as  from  1615 
to  1718.  The  sun-spot  maxima  occur  after  Jupiter  has 
swept  through  the  perihelion  half  of  his  orbit  in  most  of 
the  cases,  and  in  some  has  passed  on  to  and  even  beyond 
his  aphelion.  In  this  latter  series,  as  in  the  first,  it  is 
undoubtedly  true  that  the  sun-spot  maxima  have  in  part 
been  produced  by  the  perihelia  of  other  planets  follow- 
ing at  considerable  distances  behind  those  of  Jupiter. 

Between  1615  and  1881,  or  in  two  hundred  and  six- 
ty-six years,  twenty-four  sun-spot  maxima  have  occurred, 
as  generally  reckoned,  but  only  twenty-three  Jovian  pe- 
riods. In  other  words,  there  seems  to  be  a slow,  though 
somewhat  irregular  precession  of  the  sun-spot  maxima 
over  the  Jovian  periods,  gaining  one  sun-spot  cycle  in 
about  two  hundred  and  sixty-six  years. 

Observers  are  not  fully  agreed  as  to  the  number  of 
maximum  periods  between  1615  and  1881.  If  we  were 
allowed  to  deduct  one,  it  would  make  the  number  of 
sun-spot  maxima  correspond  exactly  with  the  number  of 
Jovian  periods.  Will  the  reader  have  the  goodness  to 
recur  to  the  table  and  observe  that  between  1761.50  and 
1788.10  — an  interval  of  26.60  years  — three  successive 
maximum  periods  are  included,  averaging  only  8.86 
years  each.  Whereas,  the  general  average  is  11.11,  or, 
allowing  the  deduction,  11.86.  If  these  three  could  be 
reduced  to  two,  without  doing  violence  to  the  facts  of 
observation,  it  would  show  such  a close  correspondence 
between  the  average  of  the  sun-spot  cycles  and  the  pe- 
riods of  Jupiter  as  would,  I believe,  convince  every  can- 


PERIODICITY  OF  SUN  SPOTS. 


253 


did  reader  that  the  latter  are  responsible  for  the  former. 
We  could  hardly  refrain  from  crying,  “ Eureka!” 

In  the  few  cases  between  1718  and  1769  where  the 
sun-spot  maxima  and  the  Jovian  perihelia  were  nearly 
contemporaneous,  the  perihelia  of  other  planets  which 
did  the  preliminary  work,  leaving  the  finishing  strokes 
only  to  Jupiter,  evidently  preceded  those  of  Jupiter. 

That  there  were  such  preceding  and  following  peri- 
helia of  other  planets  goes  without  saying.  Mercury 
is  in  perihelion  every  eighty-eight  days.  Venus  follows 
once  in  every  two  hundred  and  twenty-five  days,  while 
Earth  and  Mars  are  in  perihelion  every  three  hundred 
and  sixty-five  days  and  six  hundred  and  eighty-seven 
days  respectively.  As  to  their  exact  positions  while 
rendering  to  Jupiter  their  aid,  we  prefer  to  leave  them 
to  the  exact  calculations  of  the  practical  astronomer, 
rather  than  to  the  bungling  figures  of  an  inexpert. 

I shall  not  be  surprised  to  learn  from  those  compe- 
tent to  make  the  calculations  that  every  variation 
between  the  Jovian  periods  and  the  sun-spot  cycles  can 
be  accounted  for  by  intervening  planetary  perihelia. 

The  general  law,  I apprehend,  might  be  expressed 
thus : Let  the  mass  of  each  of  the  planets,  including  its 
satellites  and  each  of  the  planetoids  be  divided  by  the 
square  of  its  distance  from  the  sun ; then  the  sun  spots, 
in  number  and  magnitude,  will  vary  directly  as  the 
sum  of  these  quotients. 

This  expresses  the  order  only  of  the  changes.  The 
time  that  will  elapse  between  the  occurrence  of  the 
cause  and  the  exhibition  of  the  effect  will  always  be 
considerable,  just  as  our  coldest  weather  occurs  some 
time  after  the  winter  solstice,  and  our  hottest  after  the 
summer  solstice.  The  length  of  these  intervals  is  not 


254 


SUN  SPOTS. 


only  unknown  beforehand,  but  is  subject  to  considera- 
ble variations  in  different  Jovian  years. 

This  law  might  be  more  loosely  and  popularly  ex- 
pressed thus : The  nearer  the  whole  aggregate  mass  of 
planetary  matter  is  to  the  sun,  the  more  effective,  nega- 
tively, will  be  the  penumbral  shadows  or  negations  of 
energy,  or  the  greater  will  be  the  number  of  rays  of 
mechanical  motion  convertible  into  heat,  intercepted 
from  the  sun,  and  the  more  will  his  photosphere  between 
the  limits  of  the  zodiac  and  for  some  distance  beyond, 
be  cooled  and  condensed,  and  the  greater  will  be  the 
number  and  size  of  the  openings  through  the  photo- 
spheric  clouds  called  sun  spots.  But  the  intervals 
between  these  periods  of  greatest  average  proximity 
and  the  occurrence  of  the  sun-spot  maxima  are  variable 
within  certain  limits. 

But  with  these  small  concessions  to  Mercury,  Venus 
and  the  other  inferior  deities,  Jupiter,  as  might  be 
expected,  has  no  doubt  ruled  in  the  heavens  for  ages 
before  his  worship  was  celebrated  on  Mount  Olympus. 
He  dominates  in  the  matter  of  sun  spots,  but  he  is 
obliged  to  share  his  sovereignty  with  every  planet, 
every  satellite,  and  every  asteroid,  that  circles  round  the 
sun.  Every  body,  large  or  small,  situate  between  the 
celestial  concave  and  the  maculated  belts  of  the  sun, 
helps  to  cast  shadows,  or  negations,  upon  the  latter,  and 
by  so  doing  deprives  these  portions  of  the  sun  of  a cer- 
tain amount  of  mechanical  motion  convertible  into 
heat,  which  all  other  portions  of  the  sun  receive  in  un- 
diminished plenitude  and  intensity. 

These  shadows  of  intercepted  energy  cause  a relative 
cooling  of  the  photosphere  of  the  spotted  belts  and  a 
condensation  of  the  photospheric  clouds  in  “ spots,”  thus 


PERIODICITY  OF  SUN  SPOTS. 


255 


opening  rifts  through  which  we  catch  glimpses  of  the 
interior  of  the  sun. 

The  relation  between  sun  spots  and  terrestrial  mag- 
netism is  well  established  and  highly  interesting,  but  all 
that  is  known  on  the  subject  can  easily  be  found  in  the 
works  of  more  learned  writers.  It  is  highly  probable, 
though  not  yet  fully  demonstrated,  that  the  years  of  sun- 
spot maxima  are  slightly  cooler  than  the  average.  If 
so,  though  I have  not  investigated  the  subject,  it  may 
be  found  that  in  these  years  the  grasses  and  cereals, 
except  maize,  have  been  abundant,  while  during  the 
minimum  periods,  the  reverse  has  been  the  case. 


CHAPTER  VII. 


TIIE  PHOTOSPHERE  PROBABLY  COMPOSED  OF  INCAN- 
DESCENT CARBON  VAPOR. 

The  sun’s  high  palace,  on  high  columns  raised, 

With  burnished  gold  and  flaming  jewels  blazed. 

—Ovid. 

IT  is  the  almost  universally  received  opinion  that  the 
sun  and  planets  have  a common  origin.  It  is  not 
simply  suspected,  hut  fully  demonstrated,  that  a major- 
ity of  the  best  known  elementary  substances  which 
compose  the  earth  exist  also  in  the  sun.  As  to  the 
mundane  elements  that  have  not  been  discovered  in  the 
sun,  we  may  well  believe  that  their  presence  has  not 
been  detected,  through  the  imperfections  of  our  means 
of  observation. 

As  the  sun  has  only  one-fourth  the  density  of  the 
earth,  these  materials  must  be  in  forms  much  more 
expanded  than  in  the  earth. 

This  need  not,  however,  be  gaseous,  so  far  as  the 
nucleus  or  inner  core  is  concerned.  It  is  much  more 
probable,  in  my  opinion,  though  I cannot  stop  here  to 
give  the  reasons,  that  the  inner  portion  of  the  nucleus 
is  liquid,  or  possibly  composed  of  the  most  refractory 
solids,  held  in  this  form  by  enormous  pressure.  The 
outer  portions,  being  subjected  to  the  action  of  greater 
heat  and  less  pressure,  are  known  to  exist  in  the  gas- 
eous form. 

As  the  elements  of  the  earth  and  sun  are  mainly,  if 

256 


INCANDESCENT  CARBON  VAPOR. 


257 


not  entirely,  tlie  same,  it  is  highly  probable  that  they 
exist  in  the  two  bodies  in  similar  proportions.  As 
about  one-half  the  mass  of  the  earth  is  composed  of 
oxidized  silicon  or  silex,  we  may  presume  that  the 
great  mass  of  the  sun  consists  of  silicon  and  oxygen 
uncombined,  because  all  substances  in  the  sun  are  heated 
up  to  and  beyond  the  point  of  chemical  dissociation. 

This  elementary  substance  has  never  been  fused  by 
any  heat  that  can  be  produced  on  the  earth  or  concen- 
trated from  the  sun ; and  if  any  substance  could  remain 
unmelted  in  the  sun,  it  would  probably  be  silicon. 

We  tind  the  earth  to  be  finished  off  with  an  irregu- 
lar veneering  of  carbon  on  or  near  its  surface.  This 
location  of  the  carbon  on  the  earth  is  not  accidental, 
but  results  from  the  operation  of  natural  laws. 

All  the  carbon  of  the  earth,  probably  not  excepting 
even  the  small  portion  existing  in  the  form  of  the  dia- 
mond, has  been  drawn  from  the  atmosphere  by  the 
decomposition  of  carbon  dioxide,  or  carbonic  acid  gas, 
by  the  agency  of  sunlight  acting  through  the  vegetable 
kingdom.*  Of  course,  this  carbon  must  be  deposited  on 
or  near  the  surface  of  the  earth.  For  other  reasons, 
we  may  expect  to  find  the  carbon  of  the  sun  at  his  sur- 
face as  the  dividing  stratum  between  his  nucleus  and  his 
atmosphere  proper.  Though  we  meet  with  pure  carbon 
on  the  earth  in  several  allotropic  forms,  we  find  it  in 
two  conditions  only  as  affected  by  heat,  viz. : the  solid 
and  the  vaporous  or  volatilized ; never  as  a liquid  nor 
as  a gas,  unless  volatilized  carbon  be  gaseous. 

One  thing  seems  certain,  that  is,  that  the  visible  sub- 
stance of  the  photosphere  is  apparently  opaque,  and 
appears  to  us  simply  as  the  radiator  of  intense  light 

* Newton,  for  optical  reasons,  suspected  the  diamond  to  be  of  vegetable  origin. 

17 


258 


SUN  SPOTS. 


and  heat.  Speaking  of  tilings  of  which  we  know  little, 
it  may  be  said  that  probably  all  bodies  must  exist  in  a 
gaseous  or  ultra  gaseous  form  before  separation  can  take 
place  into  the  ultimate  particles.  Also,  that  all  particles, 
even  those  of  the  most  transparent  gases,  are  solid 
bodies,  and  that,  in  a highly  incandescent  condition, 
they  appear  opaque,  but  glitteringly  bright.  Carbon  in 
this  condition  might  appropriately  be  called  diamond 
dust,  if  we  can  conceive  of  dust  of  the  fineness  of  the 
ultimate  particles  of  matter. 

Still,  it  is  not  necessary  for  our  purpose  to  suppose 
that  carbon  exists  in  the  photosphere  in  the  form  of  gas. 
It  is  more  probable  that  it  exists  in  the  finely  divided 
form  which  we  see  in  fames  or  in  the  electric  arc. 

I have  seen  in  the  cabinet  of  Prof.  H.  S.  Carhart,  in 
the  Northwestern  University,  and  I presume  there  are 
many  such  cases,  an  Edison  lamp  in  which  one  arm  of 
the  carbonized  bamboo  was  ruptured  and  a portion  of 
the  carbon  volatilized.  The  carbon  was  deposited  as  a 
fine  dust  all  over  the  inner  surface  of  the  bulb,  except 
on  a fine,  straight,  perpendicular  line,  exactly  opposite 
the  remaining  arm  of  the  bamboo,  showing  conclu- 
sively that  the  volatilized  carbon  radiated  out  in  all 
directions  in  straight  lines,  like  light,  except  where  it 
was  intercepted  by  an  intervening  obstacle. 

This  tends  to  show  that  volatilized  carbon  in  a vacu- 
um is  not  gaseous.  If  it  were,  it  would  have  filled  the 
glass  bulb  and  pressed  equally  on  every  part  until 
condensed  by  cooling.  The  same  would  have  been 
true  if  the  carbon  was  in  the  form  of  vapor,  as  com- 
monly understood.  Therefore  I incline  to  the  opinion 
that  carbon,  when  not  an  ordinary  solid,  is  in  the  form 
of  impalpable  dust,  and  in  that  condition  forms  the 


INCANDESCENT  CARBON  VAPOR. 


259 


photosphere  of  the  sun.  However,  as  the  photosphere 
more  nearly  resembles  the  clouds  of  our  sky  than  any 
other  form  of  matter  we  are  familiar  with,  I shall  con- 
tinue to  speak  of  it  as  composed  of  vapor,  that  is,  car- 
bon vapor.  This  impalpable  dust  is  slightly  denser 
than  the  gases  in  which  it  floats,  and  dances  in  them 
as  freely  as  the  motes  in  our  atmosphere.  Being  slightly 
denser,  this  carbon  dust  will  seek  the  lower  levels  of  the 
sun’s  atmosphere. 

Like  nearly  all  other  forms  of  matter,  the  cooler  por- 
tions will  be  the  densest  and  will  form  the  lowest  strata, 
or  rest  upon  the  nucleus  of  the  sun.  In  fact,  it  may 
cover  this  nucleus  for  thousands  of  miles  in  depth,  as 
loosely  deposited  masses  of  incandescent  impalpable 
powder.  If  the  sun  receives  and  parts  with  his  heat 
at  the  surface,  as  I have  supposed,  the  outer  surface  of 
this  jfliotosphere  will  always  be  the  hottest  and  brightest 
part  of  the  sun,  and  the  lower  we  descend  in  imagina- 
tion through  this  vast  enveloping  cloud,  the  less  highly 
heated  and  the  less  brilliant  it  will  be  found.  Although 
it  is  not  probable  that  the  lowest  and  coolest  part  of 
these  clouds  falls  below  a white  heat,  yet,  in  contrast 
with  the  intensely  heated  and  glittering  brightness  of 
the  surface,  the  lowest  stratum  of  the  photosphere  will 
appear  entirely  black.  Whether  or  not  this  carbon 
vapor  or  atomic  dust  assumes  the  liquid  form  on  cooling 
we  may  never  know  to  a certainty.  But  even  if  it 
does  not,  it  doubtless  undergoes  changes  analogous  to 
the  condensation  and  falling  to  the  earth  of  aqueous 
vapors.  When,  therefore,  sun  spots  occur,  large  areas, 
sometimes  amounting  to  millions  and  billions  of  square 
miles,  of  this  photosphere  are  cooled,  condensed  and 
precipitated  on  the  nucleus  of  the  sun.  These  precipi- 


260 


SUN  SPOTS. 


tated  vapors  at  the  nucleus  will  now  be  exposed  to  the 
concentrated  rays  of  the  sunny  concave.  The  revola- 
tilization of  the  precipitated  carbon  will  be  resumed 
and  the  cavity  will  ultimately  be  refilled  with  photo- 
spheric  carbon  clouds. 

The  atmosphere  in  which  these  carbon  vapors  float 
is  composed  largely  of  the  gases  of  iron  and  other 
metals.  As  in  our  atmosphere  there  is  a certain 
stratum  in  which  the  clouds  float,  so  in  the  sun’s  atmos- 
phere there  is  a certain  stratum  whose  density  is  ex- 
actly adapted  to  the  clouds  forming  the  photosphere. 

PROOFS. 

As  it  has  never  yet  been  proved  that  carbon  exists  at 
all  in  the  sun,  much  less  that  his  entire  photosphere  is 
composed  of  this  element,  it  is  not  to  be  expected  that 
this  theory  will  meet  with  ready  acceptance  without 
some  considerations  tending  to  show  its  probability  at 
least.  I present  the  following : 

1.  Carbon  exists  in  large  quantities  and  in  various 
forms  in  the  crust,  on  the  surface  and  in  the  atmos- 
phere of  the  earth,  and  in  many  of  the  meteorites 
falling  on  the  earth.  Analogy  would  lead  us  to  expect 
its  presence  in  some  form  in  the  sun. 

2.  Carbon  is  the  source  of  nearly  all  the  artificial 
light  and  heat  that  exists  on  the  face  of  the  earth.  It 
warms  and  lights  our  dwellings,  cooks  our  food,  reduces 
our  ores,  drives  our  factories  and  transports  us  from  place 
to  place  on  sea  and  land.  It  figures  at  both  ends  of  the. 
electric  light.  At  one  end  it  drives  the  engine  that 
generates  the  electricity,  and  at  the  other  gives  out  the 
light  by  means  of  the  carbon  points. 

3.  In  this  last  respect  it  most  resembles  the  function 


PROOFS.' 


261 


of  carbon  in’ the  sun.  The  electric  light  is  by  far  the 
nearest  approach  that  has  been  produced  on  the  earth 
to  the  dazzling  light  of  the  sun,  which  it  much  resem- 
bles. The  particles  of  carbon  as  it  may  be  supposed  to 
exist  in  the  vapor  or  atomic  dust  of  the  photosphere, 
certainly  possess  the  peculiar  quality  of  radiating  light 
and  heat  to  a wonderful  degree,  and  seem  precisely 
adapted  to  produce  the  effects  which  we  observe  in  the 
photosphere. 

4.  If  we  reject  carbon  from  this  position  and  func- 
tion, with  what  material  will  we  supply  its  place? 
Neither  the  vapor  of  iron  nor  any  other  metal  is  avail- 
able, because  these  metals  are  proved  to  be  transpar- 
ent gases  in  the  stratum  overlaying  the  photosphere, 
whereas  the  latter  is  an  aggregation  of  opaque  fiery 
clouds.  Probably  the  only  remaining  substance  that  is 
not  volatilized  and  sent  to  the  upper  regions  of  the  sun’s 
atmosphere  is  silicon.  But  this  has  never  exhibited  any 
of  the  light  and  heat  producing  properties  of  carbon, 
and  hence  there  is  no  reason  for  assigning  it  to  this 
place. 

5.  Nature  always  employs  the  means  best  adapted 
to  secure  her  ends.  The  photosphere  ought  to  be  and 
is,  above  all  other  forms  of  matter,  the  greatest  radiator 
of  light  and  heat.  But  a good  radiator  of  heat  must  of 
necessity  be  an  equally  good  absorber.  In  both  of 
these  respects,  carbon  is  unequalled.  But  the  sun  can 
only  receive  heat  from  without  by  radiation  from  other 
suns.  If  the  sun’s  radiant  heat  came  from  within  its 
own  body,  not  only  would  it  speedily  be  exhausted,  but 
the  photosphere,  by  means  of  which  this  heat  is  radi- 
ated into  sjrnce,  would  be  the  coldest  and  darkest  part 


262 


SUN  SPOTS. 


of  the  sun,  instead  of  being  the  seat  of  his  most  intense 
heat  and  light. 

6.  It  may  be  inquired : If  the  whole  photosphere  is 
glorified  incandescent  carbon,  in  fact,  literal  diamond 
dust,  why  does  it  not  show  itself  by  means  of  the  spec- 
troscope ? I reply  that  the  spectroscope  gives  but  three 
kinds  of  spectra : the  continuous  spectrum  of  incandes- 
cent solids  and  liquids ; the  bright-lined  spectra  of 
incandescent  gases,  and  the  dark-lined  spectra  of  absorb- 
ing gases.  The  condition  of  carbon  in  the  photosphere 
being  an  opaque  cloud,  is  such  as  to  give  out  only  the 
continuous  spectrum.  This  it  does,  but  marked  by  the 
absorption  lines  of  the  overlying  gases  of  iron,  sodium, 
hydrogen,  etc.  Silicon  is  invisible  in  the  sun  for  the 
same  reason.  In  tine,  it  is  not  a matter  of  reasoning, 
but  of  fact,  that  the  most  refractory  substance  or  sub- 
stances, the  last  to  fuse  and  vaporize,  must  form  the 
core  of  the  sun.  This,  from  the  analogy  of  the  earth, 
we  should  infer  to  be  mainly  silicon. 

But  it  may  be  said  that  as  carbon  volatilized  in  the 
electric  arc,  and  even  in  the  Bessemer  furnace,  does 
give  out  bright-lined  spectra,  why  not  in  the  sun,  if  it 
exists  there  ? 

It  is  a familiar  fact  that  the  more  a gas  is  compressed 
the  more  nearly  its  spectrum  approaches  the  continu- 
ous form.  Hydrogen,  the  rarest  of  gases,  may  be  so 
compressed  as  to  yield  a continuous  spectrum. 

The  compression  under  which  carbon  exists  in  the 
photosphere  may  well  be  amply  sufficient  to  overcome  its 
reluctant  tendency  to  exhibit  bright-lined  spectra  in  the 
spectroscope.  If  it  be  an  argument  against  the  carbonic 
constitution  of  the  photosphere  that  it  gives  no  bright 
lines  in  the  spectroscope,  it  is  an  equally  good  objection 


TROOFS. 


263 


to  every  other  known  substance,  as  the  photosphere, 
whatever  be  its  constitution,  gives  out  no  bright-lined 
spectra,  but  the  continuous  spectrum  only. 

7.  Carbon  is  sui  generis  among  the  elements.  It 
sparkles  with  an  inherent  light  in  the  diamond.  In  the 
forms  of  wood,  charcoal,  mineral  coal  and  the  hydro- 
carbons, it  burns  readily  and  often  with  uncontrollable 
intensity ; while  in  the  form  of  graphite,  it  is  one  of 
the  most  incombustible  of  the  elements,  and  in  all  its 
forms  it  is  infusible  at  any  degree  of  terrestrial  heat. 
But  while  infusible,  it  can  readily  be  volatilized  in  the 
electric  arc.  It  seems  to  ignore  the  liquid  state  and 
leap  at  one  bound  from  the  solid  to  a state  nearly  re- 
sembling the  gaseous.  And  still  we  cannot  say  that  in 
this  condition  it  is  a gas.  On  the  contrary,  it  seems  to 
be  simply  fixed  carbon,  only  infinitely  subdivided  and 
shining  with  unutterable  brightness.  It  is  in  this  form, 
as  I conceive,  that  it  forms  the  photosplieric  clouds, 
brightest  and  most  rarefied  at  the  surface,  where  it  is 
exposed  to  the  concentrated  starshine  of  all  the  suns, 
and  decreasing  in  brightness,  but  increasing  in  density 
for  thousands  of  miles  downward  to  the  nucleus  of  the 
sun. 

8.  I need  spend  no  time  in  proving  that  the  photo- 
sphere is  not  a transparent  gas.  Although  it  floats  in  an 
atmosphere  of  metallic  gases,  its  cloud-like  character  is 
conceded  by  all.  What  element,  except  carbon,  is  capa- 
ble of  preserving  a finely  divided  or  even  vaporous 
form  under  a temperature  that  converts  iron  and  other 
metals  into  transparent  gases  ? 

Lastly,  in  the  economy  of  nature,  the  peculiar  func- 
tion of  carbon  seems  to  be  the  reception  and  radiation 
of  heat,  while  that  of  ether  seems  to  be  its  rapid  con- 


264 


SUN  SPOTS. 


veyance  from  sun  to  sun  and  from  world  to  world.  On 
the  earth  heat  creeps,  walks  or  runs  according  to  the 
conducting  capacity  of  the  different  substances  on 
which  it  is  dependent  for  transmission,  but  it  flies 
through  space  on  ethereal  wings  at  the  rate  of  one  hun- 
dred and  eighty-five  thousand  miles  per  second. 


CHAPTER  YIII. 


APPEARANCE  OF  SUN  SPOTS. 


Plicebi  tristis  imago 

Lurida  solicitis  prcebebat  lumina  terris. 

— Ovid. 


WE  will  here  introduce  another  figure  from  Schel- 
len’s  “ Spectrum  Analysis,”  illustrating  the  ap- 
pearance of  the  sun  spots : 


Fig.  17.— Sun  Spot  of  July  30,  1869. 

This  figure  is  most  instructive.  We  can  almost  read 
in  it  the  whole  history  of  a large  sun  spot.  It  has  evi- 

265 


266 


SUN  SPOTS. 


dently  been  a spot  of  the  size  of  the  outer  periphery  of 
the  penumbra,  but  now  in  the  process  of  healing  up. 
Granulations  from  all  sides  are  pushing  in  toward  the 
centre,  as  if  to  close  up  a wound  inflicted  on  the  sun  by 
his  own  ungrateful  children. 

The  enormous  size  of  many  of  the  sun  spots  is  incon- 
sistent with  the  idea  that  they  are  produced  by  the  splash- 
ing of  falling  meteors.  Our  earth,  if  dropped  into  some 
of  these  cavities,  would  be  like  a pebble  dropped  into  the 
crater  of  a volcano.  Bodies  of  that  size  could  easily  be 
observed  if  such  were  falling  into  the  sun.  Besides, 
their  absence  from  the  Armament  would  quickly  ‘be 
noted  by  our  eagle-eyed  astronomers.  Still  less  can  we 
conceive  of  eruptions  covering  millions  of  square  miles. 
In  fact  the  appearance  of  the  spots  resembles  nothing 
we  can  conceive  of  so  much  as  the  condensation  and 
precipitation  of  large  areas  of  solar  clouds  in  conse- 
quence of  changes  in  the  solar  weather,  quite  analogous 
to  what  we  see  on  the  earth,  where  clouds  covering  large 
districts  frequently  condense  and  disappear  in  a few 
hours.  The  edges  of  these  precipitated  clouds  would 
naturally  be  grandly  jagged  like  those  of  the  silver- 
capped  thunder  heads  that  sometimes  adorn  our  sum- 
mer skies,  only  incomparably  vaster  and  brighter ; in 
one  word,  like  the  edges  of  a sun  cloud. 

But  a change  of  weather  in  the  sun,  as  upon  the 
earth,  means  a change  in  temperature.  Our  changes 
come  from  the  sun.  The  sun’s  changes  must  come  from 
other  heavenly  bodies.  The  sun,  vast  as  is  his  mass,  can 
no  more  originate  changes  in  his  own  temperature  or 
weather  than  the  earth.  If  he  were  wholly  isolated 
from  all  extra-solar  influences,  his  own  heat  would  very 
soon  be  equally  diffused  throughout  his  entire  mass,  and 


APPEARANCE  OF  SUN  SPOTS. 


267 


all  activity  would  cease.  It  is  only  by  interaction  and 
interchange  among  celestial  bodies  that  the  eternal 
round  is  kept  up,  which  forms  the  life  of  the  world. 

The  edges  of  these  sun  spots,  thousands  of  miles  in 
depth,  sometimes  take  on  the  appearance  of  cyclones 
produced  by  the  clashing  currents  in  the  photospheric 
clouds,  as  elsewhere  explained.  Generally,  however,  as 
the  sun’s  heat  arrives  and  departs  from  all  parts  of  his 
surface  almost  equally,  the  clouds  will  be  comparatively 
calm,  and  a sun  spot,  once  formed,  will  be  likely  to 
remain  for  a considerable  time.  The  wreathen  vapors 
around  the  edges  and  projecting  into  the  abyss  seem  to 
take  on  the  fantastic  forms  of  beauty  with  which  nature 
delights  to  amuse  herself  in  her  idle  hours,  more  akin 
to  cumulus  clouds,  lazily  sunning  themselves  in  our  calm 
summer  skies,  than  to  the  rude  shocks  of  storm  and 
tempest.  The  fringes,  plumes  and  sprays  that  charac1 
acterize  some  of  the  sun  spots,  resembling  the  arbores- 
cent and  fern-like  tracings  of  frost  work  upon  glass,  are 
finely  delineated  in  another  of  Prof.  S.  P.  Langley’s  illus- 
trations. This,  on  account  of  its  size,  we  are  obliged  to 
divide.  The  other  half  will  be  introduced  as  Fig.  21. 

Another  peculiar  appearance  in  the  sun  spots  may 
perhaps  be  explained  upon  this  theory.  I refer  to  the 
grandly  corrugated  or  channelled  appearance  of  the 
sides,  as  if  raked  downward  by  Neptune’s  trident.  If 
the  body  of  the  spots,  so  to  speak,  is  produced  by  con- 
densations of  great  areas  of  fiery  clouds,  then  we  may 
suppose  that  the  edges  of  these  spots  are  in  a condition 
of  partial  condensation,  and  therefore  denser  than  the 
surrounding  photospheric  clouds.  These  partially  con- 
densed bordering  clouds  might  be  expected  to  roll  or 
glide  down  the  declivities  of  the  sun  spots,  and  the  pe- 


268 


SUN  SPOTS. 


culiar  manner  in  which  the  snn  is  supposed  to  receive 
his  light,  not  in  parallel  rays  as  from  one  sun,  but  in  all 
directions,  would  show  these  avalanches  as  bright  at  the 
bottom  as  at  the  top. 

Again ; these  vast  descending  avalanches  of  partially 


Fig.  18.—  Sun  Spot  of  March  5,  1873.—  By  Prof.  S.  P.  Langley. 

cooled  solar  clouds  would,  on  reaching  the  nucleus,  be 
arrested  and  swell  out  or  bulge  into  those  club-shaped 
forms  observed  at  the  bottom  of  the  sun  spots;  and, 
moving  horizontally  toward  the  centre,  they  would  ulti- 
mately cover  the  bottom  and  completely  fill  up  the  cav- 


BOILING  APPEARANCE  OF  SUN  SPOTS. 


269 


ity.  Owing  to  the  rounded  or  club  form  of  these  ava- 
lanches at  the  bottom,  and  the  cross  fire  of  the  light  by 
which  they  are  seen,  they  will  appear  highly  luminous, 
especially  so  by  contrast,  so  long  as  any  portion  of  the 
floor  remains  uncovered. 

BOILING  APPEARANCE  OF  SUN  SPOTS. 

Anyone  who  has  watched  what  is  called  the  boiling 
action  at  the  bottom  of  these  spots  must  have  the  most 
intense  interest  and  curiosity  awakened  to  know  the 
cause  of  this  most  interesting  phenomenon. 

The  boiling  appearance  harmonizes  admirably  with 
the  theory  here  advanced.  If  the  photosphere  is  com- 
posed of  intensely  heated  carbon  dust  or  mist,  and  the 
spots  are  immense  openings  in  the  same,  caused  by  the 
partial  cooling  and  condensation  of  this  substance,  then 
this  condensed  and  precipitated  material  will  be  much 
darker,  .as  well  as  cooler,  than  the  surrounding  photo- 
sphere. In  fact,  in  comparison  with  the  photosphere, 
the  spots  appear  perfectly  black.  This  darker  precijDi- 
tated  matter  covering  the  umbra  or  nucleus,  is  immedi- 
ately exposed  to  the  starshine  of  the  heavens.  It  will 
gradually  reabsorb  heat,  and  wTill  almost  literally  boil 
up  from  the  bottom.  This  process  will  continue  till  this 
matter  has  attained  the  temperature  of  the  surrounding 
photosphere  and  filled  the  cavity  with  the  newly  formed 
clouds.  The  process  is  slightly  analogous  to  what  we 
sometimes  witness  upon  the  earth  when  the  whole  heav- 
ens are  covered  by  thick  layers  of  cloud.  These,  by 
cooling,  condense  to  rain  and  fall  to  the  ground,  cover- 
ing its  surface  with  a plentiful  moisture.  Then  comes 
out  a hot  sun  and  vaporizes  this  moisture,  and  in  a short 
time  the  sky  is  again  covered  with  fleecy  clouds.  This 


270 


SUN  SPOTS. 


boiling  action  of  the  sun  spots,  like  a boiling  pot,  com- 
mences at  the  edges  or  penumbra  where  the  photo- 
spheric  clouds  have  been  only  partially  cooled,  and  there- 
fore soonest  recover  the  normal  temperature  of  the 
photosphere. 

FACUL^E. 

I desire  to  notice  only  one  more  of  the  phenomena 
attending  sun  spots,  and  that  is  the  faculae  or  bright 
ridges  that  frequently  surround  the  spots.  These,  by 
some  of  the  advocates  of  the  eruptive  theory  are 
ascribed  to  the  splashing  upward  of  the  photospheric 
material  by  the  downpour  of  the  cool  eruptions. 

There  are  at  least  three  objections  to  this  view.  One 
is,  that  it  is  inconceivable  that  a single  eruption  could 
be  of  such  enormous  dimensions  as  some  of  these  spots 
present.  Another  is,  that  explosive  eruptions  of  such 
extent  and  violence,  if  they  existed,  would  tear  up  the 
photosphere  in  the  wildest  and  most  disordered  forms, 
instead  of  the  gently  sloping  and  channelled  edges  of 
the  penumbra,  with  its  arborescent  sprays  and  fern-like 
fringes.  Lastly,  and  most  conclusively,  if  these  spots 
were  caused  by  explosive  eruptions,  the  ejected  matter 
would  fall  back  almost  as  soon  as  expelled,  and  the  sea 
of  fire  would  close  over  the  crater  as  quickly  as  if  it 
were  water  on  the  earth.  If,  on  the  contrary,  these 
spots,  continental  in  their  dimensions,  are  caused  by 
climatic  changes,  which  even  on  the  earth  often  extend 
through  many  days,  we  may  reasonably  expect  the  same 
to  occur  in  the  sun.  Such  we  find  to  be  the  fact. 

Now,  on  this  hypothesis,  we  should  expect  the  upper 
edges,  or  the  margins  of  the  sun  spots,  to  be  much 
brighter  than  the  general  surface  of  the  photosphere, 


FACULAS. 


271 


just  as  the  umbo  or  highest  point  of  a rounded  gilt 
button  is  always  dazzlingly  bright,  while  the  rest  is 
relatively  dull.  So  the  edges  of  the  deep  cavity  caused 
by  cooling,  condensation,  and  precipitation,  must  neces- 
sarily stand  out  more  prominently  in  consequence  of 
the  caving  in,  so  to  speak,  of  the  sun  spot.  These 
edges,  thus  left  prominent,  may  account  for  the  faculee 
around  the  spots.  This  is  grandly  illustrated  in  the 
edges  of  the  magnificent  summer  clouds  that  form  the 
rocky  mountains  of  our  western  skies.  This  feature  is 
well  illustrated  by  Fig.  19. 


Fig.  19.— From  Schellen's  “Spectrum  Analysis.” 


But  not  infrequently  spots  appear  surrounded  by 
literal  mountains  of  light.  This  is  just  what  might  be 
expected  on  the  theory  here  advocated.  A valley  in 
an  Alpine  region  of  the  sun  is  unlike  a valley  similarly 
situated  on  the  earth.  In  the  latter  case  the  valley  will 
be  hotter  than  the  surrounding  mountains.  It  will 
receive  just  the  same  amount  of  heat  by  radiation,  both 
the  mountain  and  the  valley  being  shaded  on  one  side 
when  the  sun’s  rays  are  oblique,  and  both  receiving  his 
full  radiance  when  the  rays  are  vertical.  But  in  the 
case  of  the  terrestrial  mountain,  the  beat  is  reflected 


272 


SUN  SPOTS. 


away,  while  in  the  case  of  the  valley,  it  is  reflected  from 
side  to  side,  and  nearly  all  retained. 

In  the  sun  the  valleys  are  coolest,  because  the  star- 
shine  comes  in  all  directions,  and  much  of  it  being 
received  on  the  sides  and  summits  of  the  towering 
faculae,  is  cut  off  from  the  valleys  between,  which  are 
therefore  relatively  cooler  than  the  rest  of  the  photo- 
sphere, and  therefore  more  likely  to  become  the  thea- 
tres of  sun-spot  action. 


Fig.  20.— Faculae  and  Sun  Spots,  by  Chacernce. 

This  is  illustrated  by  Fig.  20,  from  Scliellen’s  “ Spec- 
trum Analysis.” 

GRANULES  AND  PORES. 

One  of  the  most  convincing  arguments  of  the  truth 
of  this  theory  of  sun  spots  to  the  mind  of  the  writer, 
may  be  stated  thus  : 

Those  who  have  examined  the  solar  surface  most 


GRANULES  AND  PORES. 


273 


carefully,  with  the  best  facilities,  and  under  the  most 
favorable  circumstances,  find  that  the  surface,  though 
we  seek  in  vain  for  words  to  express  its  intensity  of 
light  and  heat,  is  not  of  uniform  brightness.  It  is 
mainly  made  up  of  what  are  called  granules  and  pores, 
or  alternate  specks  of  light  and  shade,  though  even 
these  granules  are  often  100  miles  in  diameter,  and  the 
pores  much  larger.  These  granules  and  pores  resemble 
rice  grains  floating  in  a lake  of  ink ; or,  perhaps,  a 
better  illustration  would  be  a western  landscape,  seen 
at  a little  distance,  at  the  moment  when  the  first  snow 
flakes  of  winter  have  scarcely  half  covered  the  black 
soil  of  our  prairies.  According  to  the  law  which  makes 
brightness  proportioned  to  heat  in  a radiant  body,  the 
granules  represent  the  most  highly  heated,  and  the 
pores  the  relatively  cooler,  portions  of  the  photosphere. 
In  other  words,  the  granules  are  little  faculse,  and  the 
pores  little  sun  spots.  These  granules  and  pores  are 
coextensive  with  the  sun’s  surface,  and  are  not  confined 
to  the  maculated  zones.  These  pores  are  caused,  as  I 
believe,  by  the  enormous  amount  of  heat  constantly 
radiated  by  the  sun,  which  cannot  fail  to  lower  rapidly 
the  temperature  of  the  solar  surface.  If  the  sun  re- 
ceived no  increments  of  heat  at  his  surface,  his  whole 
face  would  speedily  turn  to  blackness.  He  could  not 
wait  for  heat  to  be  supplied  by  the  slow  processes  of 
conduction  or  convection  from  an  inexhaustible  foun- 
tain at  his  centre,  even  if  we  conceded  its  existence. 
But  it  would  be  just  as  impossible  to  manufacture  heat 
from  nothing  at  the  centre  of  the  sun  as  to  manufacture 
matter  in  the  same  way.  Instantaneous  radiation 
requires  an  instantaneous  supply.  An  infinite  amount 
sent  forth  demands  an  infinite  amount  returned,  and 
18 


274 


SUN  SPOTS. 


the  rapidity  of  one  operation  precisely  measures  that 
of  the  other. 

If  these  pores  are  little  sun  spots  caused  by  cooling 
and  precipitation  by  radiation  from  small  areas  of  the 
photosphere,  we  have  only  to  suppose  this  cooling  to  be 
slightly  increased  from  any  cause  in  the  maculated 
belts  to  account  for  the  enlarged  areas  of  cooling  and 
precipitation  called  sun  spots. 

I need  not  say  where  I would  look  for  this  cause, 
to- wit : to  the  shadows  cast  by  Jupiter  and  the  lesser 
planets  upon  the  sun. 

This  theory  also  accords  beautifully  with  the  small 
beginnings,  slow  growth,  and  long  duration  of  sun 
spots.  Janies  Carpenter  says:  “The  first  symptom  of 
a spot  appearing  is  a tiny  speck  upon  the  photosphere. 
This  goes  on  enlarging,”  etc.  Such  a beginning  and 
evolution  are  compatible  with  neither  a meteoric  nor 
an  eruptive  cause.  If  they  were  produced  by  the 
splashing  of  bodies  of  the  size  of  the  earth,  or  even 
Jupiter  (for  the  diameters  of  some  of  these  spots  far 
exceed  that  of  Jupiter),  they  would  not  commence  at 
a point  and  gradually  enlarge.  Neither  would  they 
continue  for  weeks  and  months  with  only  slight  changes 
in  form  and  size. 

This  argument  is  equally  good  as  against  the  erup- 
tive theory,  and  seems  to  be  conclusive  against  both. 
A gaseous  eruption  would  burst  forth  with  suddenness 
and  violence,  of  full  dimensions,  and  the  displaced  pho- 
tosphere would  fall  back  to  its  place  as  soon  as  the 
eruption  ceased. 

The  writer  would  not,  of  course,  deny  the  existence 
of  immense  eruptions  in  the  sun.  But  these  are  mainly 
in  the  chromosphere,  corona,  and  upper  atmosphere. 


GRANULES  AND  PORES. 


275 


Eruptions  in  the  photosphere,  so  far  as  he  can  learn,  are 
hypothetical  only. 

The  point  to  which  the  writer  desires  to  call  the  atten- 
tion of  those  who  are  in  search  of  truth  for  its  own 
sake,  is  this,  that  the  spots  commence  in  points,  and 
open  out  more  or  less  gradually,  often  to  continental 
dimensions,  which  they  sometimes  retain  for  months. 


Fig.  21.— Sun  Spot  of  March  5,  1873.— By  Prof.  S.  P.  Langley. 

We  here  introduce  the  other  half  of  one  of  Prof. 
Langley’s  illustrations,  both  for  the  purpose  of  showing 
the  club-shaped  projections  into  the  cavity  and  the 


276 


SUN  SPOTS. 


relative  size  of  one  of  these  spots  compared  with  the 
Western  Hemisphere  of  the  earth,  shown  in  the  upper 
left-hand  corner.  If  the  original  spot,  as  seems  to  me 
probable,  was  co-extensive  with  the  outer  edge  of  the 
penumbra,  it  will  be  seen  at  a glance  how  improbable 
it  would  be  that  the  spot  could  be  caused  by  either  a 
meteor  or  an  eruption.  If  the  meteor  were  of  the  size 
of  the  earth,  it  would  be  lost  in  the  cavernous  depth  of 
one  of  these  spots. 

Neither  a meteor  of  sufficient  size,  nor  an  eruption 
of  sufficient  extent,  to  produce  such  a spot,  could  com- 
mence with  a point  and  enlarge  to  billions  or  even  mill- 
ions of  scpiare  miles.  But  if  the  photosphere  through- 
out its  whole  extent  and  in  its  normal  condition  is 
honeycombed  with  little  sun  spots,  caused  by  the  cool- 
ing from  radiation,  then  it  needs  but  a slight  additional 
cooling  in  the  maculated  belts  to  cause  first  the  coales- 
cence of  a few  neighboring  spots  and  then  their  exten- 
sion to  large  areas. 

The  theory  of  sun  spots  here  advanced  also  harmon- 
izes with  one  of  nature’s  sublimities ; the  sublimity  of 
the  minute.  Nature  is  sublime  in  the  smallness  of  her 
atoms ; in  the  minuteness  of  her  microscopic  and  ultra 
microscopic  organisms,  and  often  in  the  feebleness  of 
her  forces.  The  force  of  gravitation  acting  on  the 
earth  is  so  weak  that  it  only  pushes  the  earth  about  one- 
tenth  of  an  inch  toward  the  sun,  while  the  tangential 
force  carries  it  nearly  nineteen  miles  forward.  But 
the  cooling  shadows  that  cause  the  sun  spots  are  the 
exact  counterpart  of  gravitation  on  the  earth.  This 
shows  how  small  a change  is  required  to  enlarge  the 
small  spots  or  pores  into  the  larger  ones.  It  also  shows 
why  the  maculated  belts  are  almost  never  free  from 


GRANULES  AND  PORES. 


277 


spots,  because  the  planets  even  at  their  aphelia  cast 
slightly  cooling  shadows  on  the  sun.  If  the  breaking  out 
of  these  spots  be  attributable  to  a lowering  of  the  tem- 
perature in  the  maculated  belts,  and  I do  not  see  how  it 
is  possible  to  doubt  it,  in  view  of  their  darker  color  and 
lower  temperature,  then  it  is  manifest  that  the  photo- 
sphere within  those  belts,  notwithstanding  its  intense 
heat,  is  at  the  turning  point,  so  to  speak,  between  the 
condition  of  the  bright  granules  and  the  darker  pores, 
with  the  advantage  rather  on  the  side  of  the  pores. 
These,  according  to  Prof.  Langley,  occupy  four-fifths  of 
the  sun’s  surface,  but  emit  only  one-fourth  of  his  light 
and  heat. 


CHAPTEK  IX. 


RECAPITULATION. 


Line  upon  line,  precept  upon  precept.  — Bible. 

^IRST.  It  is  a matter  of  fact  and  not  of  conjecture 


J-J  that  Jupiter  and  the  other  planets  intercept  and 
shut  off  from  the  sun  a portion  of  the  light  from  a large 
field  of  the  starry  concave.  If  the  stars  send  forth  rays 
of  energy  capable  of  being  turned  to  heat  at  the  sur- 
face of  the  sun,  then  the  sun  will  be  deprived  of  so 
much  heat  as  represents  the  intercepted  rays  of  me- 
chanical motion  convertible  into  heat. 

2.  The  sun’s  photosphere  is  generally  believed  to 
be  composed  of  incandescent  metallic  vapors  (I  have 
suggested  carbon  vapors),  floating  in  an  atmosphere  of 
metallic  gases. 

3.  It  is  by  much  the  hottest  portion  of  the  sun.  This 
is  shown  first,  by  actual  experiment  by  Prof.  Langley 
and  others ; second,  by  its  surpassing  brilliancy,  the  tem- 
perature of  elementary  substances  being  invariably  in 
proportion  to  their  brightness  or  capacity  for  emitting 
light ; and  third,  by  analogy  of  other  celestial  bodies ; 
e.y .,  the  Earth  and  other  planets,  especially  Jupiter, 
exhibit  unmistakable  evidence  of  a common  origin  and 
nature  with  the  sun.'  These  all  receive  and  part  with 
their  commercial  or  exchangeable  heat  at  their  ports  of 
entry.  These  ports  embrace  their  whole  exterior  sur- 
face in  contact  with  the  ethereal  ocean,  by  means  of 


278 


RECAPITULATION. 


279 


which  the  imports  and  exports  of  their  foreign  com- 
merce in  the  different  forms  of  energy  are  exchanged. 
The  sun  is  the  great  entrepot  of  this  commerce  in  our 
system  where,  as  I think,  mechanical  motion  is  ex- 
changed for  liglit  and  heat,  the  fixed  capital  or  internal 
heat  of  all  these  bodies  remaining  unchanged  from  age 
to  age. 

4.  As  the  sun’s  photosphere  is  hotter  than  the  nu- 
cleus, it  cannot,  either  by  conduction  or  convection, 
receive  this  excess  from  the  interior,  and  consequently 
must  receive  it  through  the  ether  from  the  starry  con- 
cave. 

5.  Jupiter  and  the  other  planets  are  the  only  bodies 
which  can  possibly  intercept  the  energy  convertible 
into  heat,  coming  from  the  celestial  concave. 

6.  These  shadows  are  wholly  penumbra!  and  exceed- 
ingly thin,  as  the  light  and  heat  from  almost  the  entire 
starry  concave  shines  over,  under  and  around  the 
planets.  Still  these  shadows  are  not  infinitesimal  in 
their  influence.  It  is  easy  to  see  without  a diagram 
that  a portion  of  the  wave  motion,  or  energy  converti- 
ble into  heat,  from  a large  circle  in  the  starry  vault  is 
intercepted  from  the  sun  by  each  of  the  planets. 

7.  The  inclination  of  the  sun’s  equator  to  the 
ecliptic,  by  increasing  the  extreme  solar  latitude  north 
and  south,  of  all  the  planets,  widens  the  shaded  or 
maculated  zones.  This  can  be  readily  seen  from  Fig. 
15.  The  central  part  part  of  this  zone  on  both  sides  of 
the  equator  is  given  up  as  the  arena  for  the  perpetual 
battle  of  the  giants  in  the  form  of  photospheric  clouds 
from  both  the  north  and  south,  where  they  meet  in  con- 
flict, and  the  ranks  of  both  sink  vanquished  to  unknown 
depths  below.  In  the  melee  of  this  conflict  the  clouds 


280 


SUN  SPOTS. 


are  too  much  agitated  to  admit  of  the  formation  of  sun 
spots,  as  these  require  a comparatively  undisturbed  con- 
dition of  the  photosphere  in  which  they  can  slowly 
develop  and  retain  their  forms,  sometimes  for  months, 
with  only  slight  changes.  The  necessary  result  will  he 
two  u spotty  ” belts,  which  we  might  almost  predict  a 
priori  would  be  found  mainly  between  the  parallels  of 
ten  degrees  and  thirty  degrees  of  north  and  south  lati- 
tude. 

This  corresponds  wonderfully  with  the  distribution  of 
the  sun  spots. 

8.  Sun  spots  must  of  necessity  be  produced  by  some 
dynamic  change,  and  doubtless  of  that  form  which  we 
call  heat.  In  other  words,  by  an  excess  or  deficiency  of 
heat.  If  it  were  an  excess,  the  photospheric  clouds  in 
these  belts  would  become  brighter,  if  that  were  possible. 
But,  as  the  spots  appear  to  dissolve  and  turn  to  black- 
ness, it  must  be  a deficiency,  instead  of  a redundancy, 
of  heat  which  produces  the  spots. 

9.  To  the  shadows  of  the  planets  alone  can  we 
look  for  this  cooling  influence  upon  the  maculated  zones 
of  the  sun.  There  are  no  other  intervening  bodies. 

10.  As  all  the  forms  of  cosmic  energy  are  correlated 
and  interchangeable ; and  as  a portion  of  this  energy, 
exactly  proportioned  to  the  mass  of  each  planet 
divided  by  the  square  of  its  distance,  is  intercepted  from 
the  sun  and  expends  itself  upon  the  planets  themselves, 
and  as  this  is  the  exact  expression  for  gravitation,  who 
can  doubt  that  the  intercepted  energy  is  identical  with 
gravitation  and  constitutes  the  centripetal  forces  of  all 
the  planets  ? 

11.  The  sun  spots  appear  to  have  a certain  degree 
of  periodicity,  but  not  sharply  defined,  either  as  to  the 


RECAPITULATION. 


281 


amount  of  variation  or  the  times  of  the  apparent  max- 
imum and  minimum  periods.  The  variations  in  these 
spots  are  much  like  the  vicissitudes  of  the  weather  on 
our  earth,  and  produced  by  similar  causes.  The  seasons 
return  with  certainty,  but  variable  as  to  the  degrees  of 
heat  and  cold,  and  also  in  being  earlier  or  later  within 
certain  limits.  The  grand  average,  however,  is  always 
the  same.  It  is  the  same  with  the  sun  spots.  The  aver- 
age for  a long  series  is  very  nearly  uniform,  being 
nearly,  if  not  exactly,  11.86  years,  which  is  the  period 
of  Jupiter’s  annual  revolution  from  perihelion  to 
perihelion.  Now  Jupiter’s  mass  is  three  hundred  and 
thirty-eight  times  that  of  the  earth,  and  more  than 
double  that  of  all  the  other  planets  combined.  His 
mean  distance  from  the  sun  is  much  less  than  the  mean 
of  the  other  major  planets.  His  eccentricity  is  such  that, 
at  his  perihelion,  he  is  forty-five  million  miles  nearer  to 
the  sun  than  at  his  aphelion.  The  effect  of  this  combi- 
nation of  facts  is  such  that  the  planet  Jupiter,  if  the 
theory  of  sun  spots  here  advanced  is  correct,  must  dom- 
inate both  as  to  the  amount  and  the  periodicity  of  the 
spots,  although  the  other  planets  sometimes  co-operate 
with,  and  at  others  antagonize,  his  influence,  so  far  as 
the  dates  of  the  maximum  and  minimum  periods  are 
concerned ; and  this  fact  contributes  to  the  aj:>parent 
irregularity  in  the  periodicity  of  the  sun  spots. 

12.  The  heating  of  the  air  at  the  equator  and  cool- 
ing it  at  the  poles  of  the  earth  cause  a constant  circula- 
tion of  currents  from  the  equator  toward  the  poles  and 
back.  These  currents,  however,  are  regular  only  in 
their  irregularity.  The  exceptions  almost  constitute  the 
rule  in  the  case  of  the  terrestrial  currents,  owing  to  the 
variations  in  isothermal  lines  upon  the  earth,  the  differ- 


282 


SUN  SPOTS. 


ence  in  temperature  of  continents  and  oceans,  the  differ- 
ence in  friction  between  land  and  water,  and  other 
causes  existing  on  the  earth  which  do  not  exist  in  the 
sun. 

If  the  sun’s  photosphere  is  slightly  cooler  at  or  near 
the  equator  than  at  his  poles,  it  will  cause  a correspond- 
ing system  of  slow  and  gentle  currents  toward  the  poles 
and  back  again,  but  in  reverse  order,  compared  with  the 
terrestrial  currents.  The  lower  currents  will  be  the 
cooler  and  the  upper  ones  the  hotter.  The  lower  ones 
will  be  accelerated  relatively  to  the  sun’s  surface  in  pro- 
portion as  they  recede  from  the  equator.  The  upper 
ones,  on  the  contrary,  will  be  retarded  relatively  to  the 
sun’s  surface  in  proportion  to  their  distance  north  and 
south  of  the  equator.  The  inevitable  result  of  this  will 
be  that  spots  or  openings  in  the  upper  photosphere  will 
keep  pace  with  the  rotary  motion  of  the  sun  at  his 
equator,  but  will  drag  behind  more  and  more  as  they 
increase  in  latitude,  precisely  as  we  find  the  fact  to  be. 

It  is  due  to  the  writer  also  to  remember  that  no  claim 
is  here  set  up  to  anything  like  absolute  regularity  of 
operation  in  these  hypothetical  photospheric  currents. 
A resemblance  in  the  principle  is  all  that  is  claimed. 

13.  In  analogy  with  our  seasons,  the  maximum  of 
sun  spots  almost  always  occurs  after  the  sun  has  been 
for  some  time  exposed  to  the  cooling  influence  of  Jupi- 
ter’s most  effective  shadows. 

The  planet  Jupiter  has  been  mentioned  in  connec- 
tion with  sun  spots  by  almost  every  writer  on  the 
subject,  but  only  to  discredit  the  idea  that  he  could 
exert  any  agency  in  producing  them ; and  the  idea 
that  he,  with  the  other  planets,  produces  these  spots  by 


RECAPITULATION. 


283 


casting  cooling  shadows  upon  the  sun  is,  so  far  as  I am 
aware,  a novel  one. 

From  all  these  facts  and  coincidences  and  the  rea- 
soning by  which  they  are  connected,  I trust  I have 
made  a case  worthy  of  consideration  of  the  distin- 
guished men  * of  our  day  who  hold  the  keys  of  knowl- 
edge. That  they  will  give  it  a candid  and  impartial 
consideration  I know,  and  to  the  decisions  of  exact  sci- 
ence I will  bow  with  submission. 


CHAPTER  X. 


UNITY  OF  THE  PROPOSITIONS  CONCERNING  SOLAR 
HEAT,  GRAVITATION,  AND  SUN  SPOTS. 

Have  you  not  heard  it  said  full  oft’?— Shakespeare. 

I DESIRE  to  repeat  for  the  sake  of  emphasis,  the 
proposition  that  the  photosphere  is  by  far  the  hot- 
test part  of  the  sun.  This  proposition,  if  my  argument 
is  sound,  is  sustained  by  two  infallible  proofs. 

1.  The  ineffable  and  incomparable  brightness  of  the 
photosphere,  which  is  the  unfailing  index  of  ineffable 
and  incomparable  heat. 

2.  The  actual  and  accurate  determinations  of  Prof. 
Langley  and  others,  which  no  one  questions,  showing 
that  the  photosphere  is  nearly  twice  as  hot  as  the 
umbra  or  nucleus  of  the  sun. 

This  being  conceded,  all  the  main  conclusions  herein 
advocated  follow  almost  inevitably.  For  example : 

1.  The  celestial  source  of  solar  heat  seems  absolutely 
certain.  The  photosphere,  notwithstanding  its  cooling 
by  radiation,  being  nearly  twice  as  hot  as  the  interior, 
certainly  cannot  derive  its  heat  from  this  interior.  It 
must  therefore  come  from  without,  that  is,  from  the 
celestial  concave. 

2.  It  is  almost  equally  certain  that  gravitation  is 
cosmic  in  its  source,  having  its  origin  in  propulsive 
mechanical  vibrations  from  the  stellar  concave.  The 
mutual  interception  of  such  rays  is  apparently  the  only 

284 


UNITY  OF  THE  PROPOSITIONS. 


285 


possible  mode  in  which  lines  of  least  resistance  can  be 
established  and  maintained  in  the  heavens.  The  sun 
shuts  off  a part  of  these  rays  from  the  earth  and  the 
earth  from  the  sun,  making  a line  of  least  resistance  for 
both,  in  which  each  seeks  to  approach  the  other.  But 
all  forces  with  which  we  are  familiar,  manifest  them- 
selves by  motion  in  the  direction  of  the  least  resistance, 
and  doubtless  gravitation  does  the  same.  The  motions 
of  the  earth,  both  rotary  and  translatory,  date  back  to 
the  eddies  and  swirls  of  primeval  nebular  matter.  The 
sun  and  earth  are  not  tied  together  by  a strong  cable 
attached  to  each,  but  rather,  speaking  figuratively,  by 
two  invisible  * hands,  gently  pressing  them  together. 
These  invisible  hands  are  the  invisible  pulsations  of  the 
invisible  ether,  with  which  the  whole  heavens  are  tilled, 
coming  from  opposite  points  of  the  starry  dome.  The 
sun  intercepts  from  each  molecule  in  the  earth  as  many 
of  these  pulsations  or  rays  of  mechanical  force  as  there 
are  molecules  in  the  sun,  not  one  more  nor  less.  The 
earth  does  the  same  thing  by  the  sun,  so  that  in  each 
case  gravitation  is  represented  by  the  product  of  the 
masses  of  each  divided  by  the  scpiare  of  the  distance, 
and  the  two  bodies  present,  each  to  the  other,  a line  of 
motion  in  the  direction  of  the  least  resistance  in  which 
they  will  seek  to  approach  each  other,  but  balanced  and 
modified  by  other  motions  in  other  lines. 

3.  Lastly,  sun  spots  being  cooler  than  the  photo- 
sphere, and  the  heat  of  the  latter  coming  down  from  the 
solar  sky  in  all  directions,  it  would  seem  that  the  spots 
must  certainly  result  from  the  interception  from  the 
maculated  belts  of  a part  of  this  fiery  downpour.*  But 

* It  must  always  be  borne  in  mind  that,  according  to  the  theory  here  advo- 
cated, the  incoming  waves  are,  as  Prof.  Daniels  shows,  in  the  form  of  mechan- 
ical force  until  they  are  arrested  by  the  sun  and  turn  to  waves  of  heat. 


286 


SUN  SPOTS. 


the  only  screens  interposed  between  these  belts  and  the 
celestial  sources  of  solar  heat,  are  the  planets  and  satel- 
lites of  the  solar  system.  Each  of  these  three  grand 
propositions  throws  light  upon  and  confirms  the  others. 


CHAPTER  XI. 


IF. 

Much  virtue  in  an  if. — Shakespeare. 

IF  the  photosphere,  which  is  the  only  portion  of  the  sun 
ordinarily  visible  to  us,  except  the  glimpses  of  the 
nucleus  which  we  sometimes  catch  through  the  sun-spot 
openings,  were  simply  a luminous,  cloud-like  envelope, 
without  proper  motion  of  its  own,  it  would  most  cer- 
tainly accommodate  itself  to  the  motion  of  the  nucleus 
and  move  with  it  throughout  its  entire  surface,  and  all 
the  sun  spots  would  just  as  certainly  keep  pace  with  the 
motion  of  the  nucleus. 

If  there  is  a continual  downpour  of  the  upper  sur- 
face of  the  photospheric  envelope  from  the  poles  toward 
the  equator,  this  upper  surface,  having  the  slow  rotary 
motion  of  the  poles  at  its  commencement,  will  inevita- 
bly drag  behind  just  in  proportion  to  its  distance  from 
the  equator. 

If  such  currents  are  actually  approaching  the  equator 
from  the  poles  in  the  upper  portion  of  the  sun’s  cloudy 
envelope,  then  of  necessity  there  must  be  counter-cur- 
rents of  the  under  portion  correspondingly  accelerated 
on  leaving  the  equatorial  regions. 

If  this  circulation  exists,  and  I do  not  see  how  it  can 
be  doubted,  in  view  of  the  lagging  motion  of  the  sun 
spots,  then  there  certainly  is  a cooling  process  going  on 
in  the  equatorial  regions  of  the  photosphere.  On  no 
other  supposition  can  we  account  for  this  circulation. 


288 


SUN  SPOTS. 


If  there  is  such  a cooling  process  going  on  in  this 
region,  it  must  have  a cause. 

If  the  heat  radiated  by  the  sun  is  received,  as  ours 
is,  by  ethereal  undulations,  and  I have  endeavored  to 
show  that  there  is  no  other  possible  source,  then  this 
cooling  of  the  photosphere  can  only  be  effected  by  inter- 
cepting a portion  of  these  undulations.  But  certainly 
there  are  no  heavenly  bodies  interposed  between  our 
sun  and  the  stellar  concave,  except  the  planets  and  sat- 
ellites of  our  system.  What  a wonderful  confirmation 
of  this  view  we  find  in  the  fact  that  this  cooling  pro- 
cess takes  place  right  under  the  belt  of  the  heavens  in 
which  all  the  planets  revolve! 

I have  introduced  each  of  these  propositions  by  an  if. 
But  they  are  all  facts,  with  many  more,  tending  to  the 
same  result,  and  I believe  they  all  fit  and  dovetail  to- 
gether in  such  a manner  as  will,  on  full  examination, 
carry  conviction  to  every  candid  mind.  For  example: 
The  sun  spots  are  facts  ; their  periodicity  corresponding 
closely,  if  not  exactly,  to  the  Jovian  period  is  a fact; 
their  location  under  a belt  in  the  heavens  including  the 
zodiac  is  a fact ; their  lagging  motion  as  they  recede 
from  the  equator  is  a fact ; their  occasional  cyclonic 
action  is  a fact;  their  cavernous  form  and  blackened 
floor,  indicating  lower  temperature,  are  facts,  as  well  as 
Langley’s  actual  measurements  confirming  the  same ; 
the  location  of  all  the  planets  and  satellites  in,  or  near, 
the  belt  of  the  zodiac,  is  a fact;  the  inclination  of  the 
sun’s  axis  to  the  plane  of  the  ecliptic,  bringing  the  mac- 
ulated belts  of  the  sun  more  directly  under  the  planets, 
is  a fact ; the  circulation  in  the  upper  and  lower  strata 
of  the  photospheric  and  umbral  clouds  I fully  believe  I 
am  justified  in  pronouncing  to  be  a fact,  in  view  of  the 


IF. 


289 


lagging  motion  of  the  spots,  which  cannot  otherwise  be 
explained.  It  follows  that  the  maculated  belts  are  and 
must  be  relatively  cooler  than  the  rest  of  the  photo- 
sphere. 

Again,  it  follows  with  the  certainty,  as  it  seems  to 
me,  of  demonstration,  that  the  sun  spots  are  caused  by 
the  condensation  and  precipitation  of  the  photospheric 
clouds.  And  lastly,  if  I am  right,  it  follows  with  the 
cumulative  force  of  all  these  facts  combined,  that  the 
sun  receives  his  unwasting  supplies  of  light  and  heat 
by  ethereal  undulations  at  his  surface  from  the  hollow 
sphere  of  suns  by  which  he  is  surrounded. 

No  imagination  can  possibly  form  a conception  of 
the  Tophet  of  fire  and  flame  that  encircles  the  sun.  It 
has  no  resemblance  to  the  lurid  flames  of  Tartarus,  as 
painted  by  heathen  poets.  It  is  simply  brightness  and 
heat  in  their  most  intensified  forms.  The  energy  or 
ethereal  motion,  which  causes  the  sun’s  heat,  may,  and 
probably  does,  come  down  as  calmly  and  noiselessly  as 
our  sunshine,  or  even  starshine.  It  is  not  until  these 
ethereal  vibrations  bury  themselves,  so  to  speak,  in  the 
sun’s  photosphere  that  they  turn  to  heat  and  are  radi- 
ated in  that  form. 

19 


t 


CHAPTER  XII. 


CONCLUSION. 


Let  us  hear  the  conclusion  of  the  whole  matter. — Solomon. 


ITHOUT  intending  it,  and  in  spite  of  myself, 


V V my  thoughts  have  taken  the  form  of  a scheme 
or  system.  I started  out  to  commit  to  writing  a few 
thoughts  in  regard  to  solar  heat.  But  I found  that 
this  was  but  a single  link  in  an  endless  chain,  and  that 
I could  neither  comprehend  the  subject  myself  nor 
make  it  intelligible  to  others  without  following  this 
mysterious  energy  under  all  its  Protean  forms  and 
through  the  entire  circle  of  its  manifestations. 

Notwithstanding  the  feeble  and  halting  steps  by 
which  I have  endeavored  to  trace  the  exhibitions  of 
this  energy  in  nature,  the  system  itself  is  grand  beyond 
the  powers  of  thought  or  expression. 

Of  course  the  fundamental  principle  of  the  only  true 
system  is  the  “ conservation  of  energy.”  But  many 
writers,  with  whom  I would  not  for  a moment  presume 
to  compare  myself,  at  least  for  research  in  special 
departments,  seem  to  understand  this  principle  in  an 
exceedingly  limited  sense.  For  example,  it  is  not 
uncommon  for  them  to  speak  of  all  the  heat  of  the  sun, 
except  the  two  hundred  and  thirty  millionth  part,  inter- 
cepted and  utilized  by  the  planets,  as  wandering  off 
into  the  depths  of  space  and  being  lost,  forgetting  that 
heat  and  all  forms  of  energy  are  motion,  or  at  least 


290 


CONCLUSION. 


291 


manifest  themselves  by  motion.  In  the  case  of  intense 
heat,  it  is  a rapid  vibratory  motion  of  incandescent 
matter.  But  certainly  there  can  be  no  motion  where 
there  is  no  matter.  If  the  ethereal  waves  should  ever 
arrive  at  a point  where  there  is  no  ether  to  carry  them 
farther  and  no  material  bodies  to  arrest  them,  it  is  not 
pretended  that  they  could  longer  exist  in  any  form. 
This  would  certainly  be  their  Tarpeian  rock,  from  which 
they  would  leap  from  existence  into  annihilation.  The 
same  fate  would  await  the  doctrine  of  the  conservation 
of  energy.  Again,  this  two  hundred  and  thirty  mill- 
ionth part  of  the  heat  of  the  sun  received  by  the  earth 
and  other  planets  is  again  radiated  into  space  as  fast  as 
it  is  received,  as  the  earth  is  not  growing  hotter.  This 
is  surely  not  inconsiderable  in  amount.  But  it  is  wholly 
disregarded  by  many,  I may  almost  say,  by  all.  Again, 
the  starry  concave  is  studded  with  millions  of  millions, 
yea  billions  of  billions,  of  suns  beyond  the  power  of  the 
imagination  to  grasp  or  of  figures  to  express.  Appar- 
ently only  an  infinitesimal  quantity  of  heat  reaches  us 
from  these  suns.  Consequently  all  the  heat  of  the  stars 
is  ignored  so  far  as  our  system  is  concerned.  Again, 
gravitation  is  as  universal  as  light  and  heat ; is  as  really 
a form  of  working  energy  as  the  former ; is  expended 
and  renewed  as  incessantly ; must  have  a source  and  a 
destination,  as  much  as  light,  heat  or  any  other  form  of 
energy;  in  other  words,  must  form  a link  in  an  end- 
less chain  or  an  arc  of  a circle.  In  fact,  it  is  not 
expressing  the  truth  too  broadly  to  say  that  energy 
never  stands  still.  Yet  so  far  as  I know,  no  writer  has 
seriously  undertaken  to  bring  this  great  force  in  nature 
into  correlation  with  other  forms  of  energy. 


292 


SUN  SPOTS. 


The  main  propositions  herein  advanced  and  de- 
fended are  three : 

1.  That  the  universal  ether  is  still  the  abode,  though 
in  diversified  forms,  of  the  whole  sum  total  of  all  the 
energy  with  which  it  was  replete  in  the  nebular  state, 
when  the  heavens  were  aglow  and  “the  elements  dis- 
solved with  fervent  heat.”  This  energy  in  varied 
forms,  however  insensible,  is  to  the  last  iota  still  extant, 
or  else  conservation  has  failed  to  conserve.  It  leaves 
the  suns  as  heat,  but  during  long  progresses  through 
space  turns  to  mechanical  force  and  other  forms  of 
energy,  only  to  reappear  as  heat  in  the  solar  orbs  ad 
eternum ; perhaps  by  electrical  vibrations  of  atomic 
diamond  dust  in  the  photosphere ; perhaps  simply  by 
arrested  mechanical  motion ; perhaps  by  a change  in 
vibration  analogous  to  the  sympathetic  motion  which 
one  vibrating  body  awakens  in  another.  In  fact,  every 
metamorphosis  of  energy  is  the  arrest  of  one  kind  of 
motion  and  the  inauguration  of  another. 

2.  That  this  same  energy  in  the  form  of  mechanical 
motion  pervades  all  space,  moving  in  right  lines  and 
attacking  every  molecule  and  every  mass  equally  on 
every  side,  except  where  intercepted  by  one  molecule 
or  mass  from  others.  The  nearer  the  intercepting 
bodies  are  to  each  other,  the  more  rays  of  force  they 
will  intercept  from  each  other  in  the  proportion  of  the 
inverse  squares  of  the  distances,  thus  marking  lines  of 
least  resistance  in  which  all  the  bodies  will  infallibly 
seek  to  approach  each  other.  All  will  recognize  this  as 
gravitation. 

3.  The  planets,  satellites  and  planetoids,  revolving 
around  the  sun  within  or  near  the  belt  of  the  Zodiac, 
must  and  do  intercept  from  the  sun’s  equatorial  regions 


CONCLUSION'. 


293 


a portion  of  the  emanations  of  a wide  belt  of  the 
heavens.  All  will  admit  that  these  emanations,  how- 
ever feeble,  or  however  puissant,  are  in  the  form  of 
motion  or  energy  convertible  into  heat.  These  inter- 
ceptions or  shadows  must  lower,  however  slightly,  the 
temperature  of  the  equatorial  regions  of  the  sun,  and 
hence  condensation  and  precipitation  of  portions  of  the 
photospheric  clouds,  exhibiting  the  phenomena  of  sun 
spots. 

This  trinity,  inexpressibly  grand,  infinitely  compre- 
hensive, comprises  a cycle  so  vast  as  to  include  the 
light  and  heat  of  every  sun  and  every  known  form  of 
energy. 


4 

* 


